Do You Have Eyelash Mites? Up To 80% Of People Do!

Just reading the words “eyelash mites” is probably freaking you OUT. Well, never fear, they are as creepy as they sound, but they can be banished. As many as 80% of the population currently have eyelash mites, or Demodex folliculitis, right now.

These worm-like parasites feed on oils and debris in the lash follicles and lash line. At night they leave the hair follicles and come out to mate, (I know) so making lash cleansing a part of your evening regime is critical. Once a mite goes back inside your eyelash follicle, you won’t be able to get to it.

One thing is for sure – when these creeps overpopulate in your lash line, they can cause big problems, like redness, itching, swelling of eyelids, eye infections and permanent loss of eyelashes! If mites die inside the lash follicle, their eggs, clawed legs, spiny mouthparts, salivary enzymes, and particularly their decaying bodies could also cause these nasty symptoms.

5 Signs That You Have Lash Mites:

  • Cylindrical crust/dandruff, like a clear tubular cuff that is attached to the eyelid and encircles the base of your eyelashes
  • Chronic redness to lash area
  • Itching at the lash root, especially in the morning
  • Unexplained eyelash loss
  • Foreign body sensation (Feeling like you have something in your eye)

*If you think you are suffering from a Demodex folliculitis infestation, and you have multiple symptoms listed, you need to see a doctor for prescription treatment.

How Can You Prevent Eyelash Mites?

  • Do NOT share makeup or makeup brushes! These parasites can also be carried on your skin, so do not share your makeup, ANY type of makeup, with another person. It’s all too easy to borrow a liner, mascara, or concealer in the nightclub bathroom, but if you do, you may be taking home more than just a cute guy.
  • Wash sheets, towels and especially pillowcases regularly in hot water and dry them thoroughly on a high heat setting. If a friend or loved one becomes infected, resist close facial contact and do not share pillows, towels, or bedding. So, basically, your love life is on HOLD.
  • 50% of all cases of eyelash parasites come from not removing makeup properly, so put down the wine glass and shampoo your lashes.

How To Keep Your Lashes and Brows Clean

The best preventative measure is keeping your lashes sparkling clean and free from daily grime. This is especially important for people wearing eyelash extensions. Luckily, I know just the thing…

BeautyGARDE oil-free lash and brow shampoo is not just the best makeup remover you will ever use, it is also the best cleanser you will ever use. Makeup debris gathers in your lash line, and even after you wash your face, you’d be amazed at how much makeup is still hiding there. It’s the perfect setting for a bug party -Yikes.

This shampoo features a squeezable tube fitted with a locking charcoal brush head.
Why a charcoal brush? Because charcoal is anti-bacterial and anti-microbial, and cannot support bacterial growth or Demodex folliculitis. The soft brush deep cleans in between every lash, flushing out makeup debris and the parasites hiding in it. And also won’t pull or tear your lashes, and protects the delicate skin around the eye area. Imagine the difference between wiping your teeth with a washcloth versus brushing them with a toothbrush! It’s a good analogy for the difference between regular face washing, and switching to lash shampoo. The whole cleansing process only takes a couple of minutes, but the impact is big. Let’s put it this way: If you wear makeup, you need this.

Even better, this product is 100% safe for use on eyelash extensions. Lash extension wearers have an especially tough time getting their lashes truly clean. Pads and wipes leave behind annoying and sometimes painful lint, and rubbing or scrubbing can twist and tear extensions. This is an oil-free makeup remover, which means it will not compromise the glue on your lash extensions.

See all our oil-free products that are safe for lash extensions here

Back to Expert Makeup Advice

What Are Eyelash Mites?

The eyelash mite is also known as demodex folliculitis. It is a parasite that is found in the hair follicles of our faces. They can be found in the nose, the cheeks, and particularly on the eyelash area. They are usually innocuous, and most people go about their business never noticing that they are there.

There are about 65 different species of demodex, and only two of those are known to attack people. They are the demodex brevis and the demodex folliculorum. Eyelash mites are only of the demodex folliculorum variety.

The demodex brevis is usually found on the sebaceous glands, and the demodex folliculorum is found on hair follicles. The two species are found on facial areas, particularly on areas near the cheeks, forehead, chin, eyebrows, eyelashes, and nose. They also can be found in other areas of the body. They have been found in the hairs of the ear canal, the nipple, the groin, the chest, the forearm, and the penis.

The mites are too small to see with the naked eye. They are so small that there may be over 25 mites on one eyelash follicle. They do not like light. They may come out of the hair follicle at night and crawl around your skin. The females are slightly rounder and bigger in size compared to the males, and they undergo internal fertilization.

Anyone may get the parasite, although babies are born without any trace of them. Older people are more likely to get them because their immune system is weaker. It is estimated that over eighty percent of Americans have them. The parasites position themselves face down in the hair follicle and eat waste and buildup from our skin.

They are really harmless creatures, and scientists have said that there might be a symbiotic relationship between them and people. The claim is that they take away dirt and oil from our follicles and we allow them to live off of us.

Despite the fact that the amount of these parasites might be very high, doctors usually don’t treat the patient for them. However, if their presence is accompanied by irritation, inflammation, or infection, then something needs to be done about them. The condition of their number being too high is called demodicosis. Sometimes, a high number of the mites in a single follicle causes the eyelash to fall out.

The Causes of the Problem

When mites build up to a high level, then there can be issues. Too many of them can cause your face to become infected, and your eyelashes may fall out. The issue is caused many times by too much secretion of oils and sometimes by the application of excessive makeup. The situation can be made worse by not washing your face before you go to sleep. It is estimated that 50% of Americans have the parasite because they sleep with their eye makeup on.

Proper hygiene is always very important, and you should wash your face before falling asleep. Eye makeup can be the cause of the growth of bacteria. Mascara particularly is known as being the cause of this growth. You need to wash your makeup brushes and use clean mascara wands to make sure that you don’t promote the presence of the mites.

Eyelash Mites Symptoms

People who have strong immunity may have no symptoms from the mites. Those who have weakened immunity (from diseases like HIV or leukemia) or have a lot of stress may show symptoms. This particularly happens as they multiply.

The following are eyelash mite symptoms:

– The mite bites can many times result in skin disorders, inflammation, or itching. The itching happens more often in the morning. The mites leave the follicles at night to mate and lay eggs and come back to the follicle in the morning.

– Rosacea is another symptom that come from the mites. Rosacea may not come as a result of the mites themselves but from the bacteria in their feces.

– Blepharitis. This is eyelid inflammation that consists of crusty, swollen, reddened, burning, and itchy eyelids.

– People may get acne from the mites.

– Severe infestation of the mites can lead to eye and skin infection.

Your doctor will probably ignore the presence of the mites unless there are definite symptoms that you are suffering from.

Eyelash Mites Treatment

After you have determined that you have these parasites, and they are causing symptoms, it is necessary to know how to treat them. The following is a discussion of these treatments. Luckily, there are a number of treatments that are available. If one doesn’t work, then you can try another.

1. Proper Eyelid Cleansing

The most important thing that you can do to rid yourself of these mites is to completely clean your eyelids. This includes the edges of your eyelids. What you want to do is remove all of the oils that the mites eat. You can try baby shampoo, tea tree shampoo, or any other appropriate cleanser to make sure that your lids are completely cleaned. Also, you may use no-tear baby soap to wash your face twice a day. This will be a good way of making sure that you keep the mites off of your face.

2. Over-the-counter Antibiotic Treatments

The second way to treat the mites is the use of antibiotic ointment. It is important to make sure that the ointment that you use is tested so that it doesn’t negatively affect your eyes. One way to ensure this is to get a recommendation from an ophthalmologist. You may use Tobradex or a drop of Tetravisc to resolve the problem.

3. Tea Tree Oil

Tea tree oil is a good substance to remove the mites from your eyelashes. You can rub the oil on your lashes every night for six weeks. This should resolve the issue. You need to be careful, though, that you don’t get the oil in your eyes.

Any product that contains tea tree oil will help with the removal of the mites. This is particularly so for the kind of mites that reside in your sebaceous glands.

Tea tree oil has been recommended by Dr. Oz and others. If used properly, it can kill the mites on your lashes as well as the eggs in your follicles.

You can also apply 5% tea tree oil ointment daily to your lids to stop mating and re-infestation from the skin around the eye.

4. Lavender Oil

In the same way that you can use tea tree oil, you can use lavender oil to kill the mites. You should apply or rub lavender oil to your eyelids every night before you go to sleep.

5. Stop Using Mascara

You should stop using mascara until the eye mites on your lashes go away. You also need to throw away your old makeup that you were using when you had the infestation. This is to prevent further contamination. It is also important that you do not share eye makeup with anyone else.

Some Other Tips on How to Treat Eyelash Mites

– If you are married or have a significant other, you need to make sure that they are checked for face mites. The mites spread via casual contact and can move easily from one person to another.

– Make sure that your pets are checked. They may also carry these parasites. Although the mites that affect dogs are of a different type, human eyelash mites can also be hosted by pets.

– Purchase new pillows and bed sheets because they may be carrying the mites. If you don’t do so, you can easily become re-infected from your bedding.

– There are specially formulated products on the market to deal with mites. One of these is Cliradex.

In conclusion, facial mites can actually help remove dirt and oils from your face. They have a somewhat of a symbiotic relationship with people. However, when their number gets to be too high, they can cause problems such as inflammation and irritation. Luckily, there are many ways that you can rid yourself of the parasites. If you have a significant problem with them, then you should pursue the care of your physician.

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Eyelash mites are very real, here’s what you need to know

LITTLE ROCK, Ark. — You may not want to hear this, but eyelash lice—also known as eyelash mites— well, they’re something we all have.

They’re microscopic and you can’t see them, but doctors say they can get out of control.

It was this post from last week that has people squeamish:

Post by thv11.

Eyelash lice. Is it really a thing?

“It is really a thing, we call it Demodex,” Dr. Sarah Lunsford verifies. Dr. Lunsford is an optometrist and said that it’s more common than you might think.

“They’re actually little mites and they live in the hair follicles. We see them on eyelashes on people.”

What’s not common is a visible abundance of them.

What causes it?

According to Dr. Lunsford, they’re more common among people with weaker immune systems and with eyelash extensions, but mainly when they’re not kept clean enough.

“She got the eyelash extensions, had symptoms and her eyes were itchy and her eyelids were bothering her. She came in and she had lots of Demodex signs on her eyelashes and had to have those extensions removed,” Dr. Lunsford said.

Demodex do exist but can be treated. Dr. Lunsford said not to worry too much.

“We all have some of them. It’s just when they get out of control that they cause symptoms and problems for us.”

Those symptoms are dry, red, watery and burning eyes. Also, the mites become visible with inflammation.

The most common treatment for those negative symptoms is washing your eyelashes carefully with baby shampoo and Tea tree oil.

If you have something you’d like verified, it’s easy. Email [email protected] or reach out on social media.

RELATED:

Mange is a parasitic skin disease caused by microscopic mites. Two different mange mites cause skin disease in dogs. One lives just under the surface of the skin (sarcoptic mange – see handout “Sarcoptic Mange in Dogs” for more information), while the other resides in the hair follicles (demodectic mange). Although both mites share similar characteristics, there are also important differences. It is important not to confuse the two types of mange because they have different causes, treatments, and prognoses.
Image via Wikimedia Commons / Joel Mills (CC BY-SA 3.0.)

What causes demodectic mange?

Demodectic mange is caused by Demodex canis, a parasitic mite that lives in the hair follicles of dogs. Under the microscope, this mite is shaped like a cigar with eight legs. Demodectic mange, sometimes just called ‘demodex’ or ‘red mange’, is the most common form of mange in dogs.

“As long as the body’s immune system is functioning properly, these mites cause no harm.”

All normal dogs (and many humans) have a few of these mites on their skin. As long as the body’s immune system is functioning properly, these mites cause no harm.

Demodectic mange most often occurs when a dog has an immature immune system, allowing the number of skin mites to increase rapidly. As a result, this disease occurs primarily in dogs less than 12 to 18 months of age. As the dog matures, its immune system also matures.

Adult dogs that have the disease usually have weakened immune systems. Demodectic mange may occur in older dogs because function of the immune system often declines with age. Dogs who have a weakened immune system due to illness or certain medications are also susceptible to demodectic mange.

Is demodectic mange contagious?

No, demodectic mange is not contagious to other animals or humans. Demodex mites are transmitted to puppies from their mother during the first few days of life. Since the mite is found on virtually all dogs, exposure of a normal dog to one with demodectic mange is not dangerous, as the immune system must be depressed for mange to develop.

“Demodectic mange is not contagious to other animals or humans.”

Why doesn’t the immune system mature correctly in some dogs?

Development of the immune system is under genetic or hereditary control. An affected dog often has littermates that are also affected. Owners of littermates should be alerted to watch for the development of mange in their puppies. Because the disease is due to a genetic defect, affected dogs should not be bred, and the parents of the affected dog should not be bred again.

What does demodectic mange do to the dog?

Surprisingly, a dog with demodectic mange usually does not itch severely, even though it loses hair in patches. The hair loss usually begins on the face, especially around the eyes. When there are only a few patches of hair loss, the condition is called localized demodectic mange. If the disease spreads to many areas of the skin, the condition is called generalized demodectic mange.

How is demodectic mange diagnosed?

“Your veterinarian will take deep skin scrapings and examine them under the microscope to diagnose this disease.”

Your veterinarian will take deep skin scrapings and examine them under the microscope to diagnose this disease. The finding of larger than normal numbers of Demodex mites in skin scrapings confirms the diagnosis. Occasionally, the disease will be diagnosed by means of a skin biopsy in dogs that have chronic skin infections that have not responded appropriately to treatment.

How is demodectic mange treated?

The localized form is usually treated with topical medication. The generalized form requires more aggressive treatment using special shampoos and dips, along with oral medication. Shampooing with special cleansing shampoos containing benzoyl peroxide helps to flush out and open the hair follicles prior to dipping. A separate handout is available to describe the dipping process (see handout “Demodectic Mange – Dipping Instructions for Dogs”).

There are also several ‘spot on’ topical treatments, such as imidacloprid and moxidectin. These medications are used ‘off label’ for the treatment of demodicosis. The term ‘off label’ describes the use of a drug for conditions other than what it was approved for.

There is an injectable form of doramectin, which can also be used for off label treatment of demodex. Your veterinarian will discuss the benefits and risks of these medications with you.

In some cases, especially dogs with generalized demodectic mange, secondary skin infections complicate the condition, requiring antibiotic therapy. Because dogs with skin infections often have very red, inflamed skin, demodectic mange is often called ‘red mange’. Your veterinarian can help you determine whether or not your dog has a skin infection in addition to demodectic mange.

Are there any problems with topical treatment?

The dip commonly used for demodectic mange contains the insecticide amitraz. It must be used very carefully because it is a strong insecticide that can cause serious side effects, both to your dog and to you, if not used properly. Your dog may experience vomiting and sedation for twenty-four to thirty-six hours following each application. Most of these problems will resolve without medical intervention. If your dog reacts in this manner, you should dilute the next dip with 25% more water. If you are using a ‘spot on’ topical treatment, you may see drooling if your dog licks the medication.

“Amitraz must be used very carefully because it is a strong insecticide that can cause serious side effects, both to your dog and to you, if not used properly.”

Since most dogs develop tolerance to the dip as they are repeated, your dog is less likely to have side effects with each subsequent treatment. After receiving two to three dipping treatments at seven-day intervals, skin scrapings should be repeated and examined for the presence of live mites or mite eggs. The results of these skin scrapings will determine whether further treatment is needed.

I heard that there is a drug that can be given orally for demodectic mange. Is that true?

Yes, under certain conditions.

Ivermectins are a class of drugs that are approved for prevention of heartworm disease in dogs and cats. Certain ivermectins are used to treat parasites on cattle. The cattle preparation has been used orally for demodectic mange in some dogs. However, ivermectin is not approved for use in treating dogs with mange, so its use to treat mite infestations in dogs is off-label.

Ivermectin is a very strong drug that can cause severe side-effects, including death, if it is not administered properly. It is extremely important to follow your veterinarian’s instructions and cautions carefully, as their directions may be very different from those on the label. Veterinarians do not generally recommend ivermectin for use in Collies, Shetland Sheepdogs, Australian Shepherds, Old English Sheepdogs, or any other herding breed because they are sensitive to the medication.

There are a few other oral medications that may be used off label in the treatment of the demodex mite. These include milbemycin oxime (the active ingredient of Interceptor® and Sentinel®), afoxolaner (NexGard®), and fluralaner (Bravecto®). Your veterinarian will help you decide which oral or topical medication is best for your dog.

What is the prognosis for my dog?

Treatment of demodectic mange is generally successful. However, if the immune system is weakened, neither the mites nor the infection may respond to treatment. With generalized demodicosis, successful treatment may take a long time, and may require regular skin scrapings to check the progress of the treatment.

Following successful treatment, is it likely to recur?

“It is important to treat as soon as a relapse occurs to minimize the possibility of developing uncontrollable problems.”

Because the immune system does not mature until 12 to 18 months of age, a dog with demodectic mange may have relapses until that age. In addition, dogs with suppressed immune systems may be susceptible to relapse. It is important to treat as soon as a relapse occurs to minimize the possibility of developing uncontrollable problems. Relapses are usually recognized 3-6 months after treatment is discontinued.

Contributors: Ernest Ward, DVM; Updated by Amy Panning, DVM © Copyright 2018 LifeLearn Inc. Used and/or modified with permission under license.

What is demodecosis?

Demodecosis is a parasitic skin condition, caused by demodex mites. These microscopic mites can be found on the skin of all animals, but in some cases they proliferate to excessive levels and cause clinical signs. This increase is often associated with a suppressed immune system, although this is not always the case.

While demodecosis is more common in dogs than cats, there are two species of demodex mites that can affect cats: Demodex cati and Demodex gatoi. Demodex catiis typically found within the hair follicles, while D. gatoi is more likely to live on the surface of the skin. Cats of all breeds and ages can be affected by demodex mites, although Burmese and Siamese cats do appear to be overrepresented.

Demodex mites are species-specific. Each species of demodex mite only has one host species on which it can survive. This means that an infected dog cannot transmit demodex mites to a cat, and vice-versa. Additionally, demodex mites found on cats and dogs do not spread to humans.

What are the clinical signs of demodecosis?

Demodex mites can be associated with localized or generalized disease. Signs vary, depending on the species of mite involved.

Demodex cati is frequently associated with hair loss, skin inflammation, and crusting. The skin lesions may be itchy, though this is not always the case. In some cases, cats may have only localized skin issues; commonly on the face, head, and neck. In other cases, lesions may spread to involve the entire body. Demodex cati can also be a cause of recurrent ear infections.

Demodex gatoi frequently causes severe itching, inflammation of the skin, and crusts along the trunk and limbs. In some cases, cats may develop ulcers on the lips or small scabs (military dermatitis) across the entire body. In most cases, the skin issues associated with Demodex gatoi are clinically indistinguishable from allergic skin disease. Therefore, demodecosis should be considered a possibility in any cat suspected of having allergic skin disease. Some cats infected with Demodex gatoi may be completely asymptomatic with no visible skin lesions.

How is demodex diagnosed?

Diagnosing demodex typically requires a test known as a skin scrape. In this test, your veterinarian will use a scalpel blade to scrape off some of the outer layers of skin cells, removing demodex mites that may be living on the surface of the skin or in the hair follicles. The samples obtained via the skin scrape will be examined under a microscope to assess for the presence of demodex mites.

Other tests that may be used to assess for the presence of demodex include an acetate tape preparation, in which a piece of transparent tape is applied to your cat’s skin to lift off any parasites that may be living on the surface. This piece of tape is then examined under a microscope for the presence of demodex mites. Hair pluck samples may also be examined under the microscope, looking for demodex mites that may be found within the hair follicle. Less commonly, more invasive tests such as skin biopsy may be required to visualize the demodex mites within the hair follicle.

In cases of ear infections caused by demodex, the mite is often discovered while attempting to the find the cause of recurrent ear infections. This workup frequently involves taking swabs of otic debris from the ear canals, then examining this debris under a microscope. If a cat is infected with demodex, demodex mites may be seen during microscopic examination of the otic debris.
Image viaWikimedia Commons / Joel Mills (CC BY-SA 3.0.)

How did my cat contract demodex?

“Demodex cati is not contagious and cannot be spread between cats. Demodex gatoi, however, is contagious to other cats.”

Demodex cati is not contagious and cannot be spread between cats. Cases of localized infection do not necessarily indicate an underlying cause, however, generalized infection may indicate underlying immunosuppression that is allowing the mite to multiply out of control. In cases of generalized Demodex cati infestations, your veterinarian may recommend testing for Feline Leukemia Virus, Feline Immunodeficiency Virus, or other immunosuppressive conditions. Additionally, Demodex cati may be associated with medications that can suppress the immune system; your veterinarian will take a thorough history to ensure that your cat is not receiving any medications that may lead to this condition.

Demodex gatoi, however, is contagious to other cats. Because some cats may remain asympomatic even if infected, it is important to consider the possibility of asymptomatic carriers if you have a multi-cat home and issues with Demodex gatoi in one cat.These cats may spread demodex mites to other cats in the home, even if they are not showing signs of skin disease.

How is demodex treated?

The treatment of feline demodecosis depends upon which specific demodex species is involved.

“Although not all infected cats have a suppressed immune system, many cats do and these cats cannot be successfully treated until the immunosuppression is addressed.”

With Demodex cati, successful treatment depends upon identifying and addressing the underlying cause of immunosuppression. Although not all infected cats have a suppressed immune system, many cats do and these cats cannot be successfully treated until the immunosuppression is addressed. As immunosuppression is addressed or ruled out, antibiotics are given to address secondary bacterial skin infections and medication will be administered to kill the demodex mites. The options for addressing Demodex cati mites include topical treatments (lime sulfur dips), oral medications (ivermectin or milbemycin), as well as other options. Each treatment has a unique set of benefits and side effects, so your veterinarian will work with you to determine the best treatment for your cat.

In cats with Demodex gatoi, successful treatment relies on treating all cats in the household. The treatments used to treat Demodex gatoi are similar to those used for Demodex cati, including lime sulfur, ivermectin, milbemycin, or other treatments.

What is my cat’s prognosis with treatment?

In most cases, demodecosis in cats can be successfully treated. The prognosis for cats infected with Demodex gatoi is very good, if all in-contact cats can be treated to prevent re-infection. The prognosis for cats infected with Demodex cati depends on the ability to manage any underlying immunosuppressive conditions, but treatment is typically effective if underlying immunosuppression is ruled out or eliminated.

Contributors: Catherine Barnette, DVM © Copyright 2017 LifeLearn Inc. Used and/or modified with permission under license.

AnonymousJuly 18, 2012 at 9:53 PM

There is nothing ‘cool’ about this damnable parasite, the Demodex Mite. Where the incorrect information that they don’t produce waste originated from, God only knows. From Emeds: Accumulation of waste material of the follicle mite may occur in affected follicles or sebaceous glands. Electron micrographs of the mite surface and feces show bacterial, viral, and rickettsial elements.
Not cool at all…
I am currently experiencing an infestation of these little bastards, because of this very “uncool parasitic, opportunistic mite.” During a recent illness, my immune system must have been weakened, added to high stress as a business owner.
These mites will proliferate, multiplying to unbelievable numbers soon becoming an infestation on your face, in your eyes, nose, eyebrows, hairline, scalp.
And yes, they do leave waste, that your body will absorb compromising your lymphatic system. They come alive at night, using your eyes as it’s disgusting mating ground. Add to all the above, at this stage, with your eyes closed, oddly, some of those infected are able to see the little bastards having an orgy on thier eyeballs.
No know pathogens?
Pathogenic role of Demodex mites in blepharitis, Demodectic Rosacea,
Read an accurate articles regarding this ‘fun party animal’ destroying your face.
Research indicates that human demodex is a conditional-pathogenic parasite. The disorder occurs as the result of a large infestation of demodex mites on the skin, combined with a weakened immune system. The physical, chemical and mechanical stimulation of the skin from the mites can cause the immune system to react in extreme ways. Local allergic inflammation, erythema, papules and pustules are all reactions by the immune system.
Are Demodex Mites contagious?
Yes, demodex mites are very contagious. They are acquired through physical contact with infected persons; for example through kissing, hugging, using the same towels, etc.
What damage can Demodex do?
Demodex mites live inside the sebaceous glands and hair follicles, sucking nutrients from the hair roots and damaging the cell walls. After mating they burrow into the skin, laying eggs, introducing bacteria and infection to the skin. Throughout the five phases of their life cycle, these mites destroy the skin by excreting wastes and secretions, laying eggs and dying within its layers. After death, their corpses become liquid and decompose inside the skin.
Without diagnosis, quick and proper treatment, this condition causes increased damage to health, structure and beauty of the skin. The destruction of the skin becomes more and more severe as the condition persists, leaving the facial skin rough and ugly.
Pathologic changes to the skin,enlarged opening of the hair follicles, widened pores, enlarged and damaged capillaries, hyperplasia of cells and even rhinophyma (growth of the nose and central facial areas) can develop. Given this, it is not difficult to imagine the extent of the damage that the mites cause.
Apart from its higher density in patients with rosacea, Demodex mites have also been suggested as a cause of other skin diseases such as pityriasis folliculorum, perioral dermatitis , scabies-like eruptions, facial pigmentation, eruptions of the bald scalp, demodicosis gravis, and even basal cell carcinoma.
I grow weary of the disinformation concerning the Demodex mite.

ReplyDelete

These microscopic mites live on your face

You almost certainly have animals living on your face.

You can’t see them, but they’re there. They are microscopic mites, eight-legged creatures rather like spiders. Almost every human being has them. They spend their entire lives on our faces, where they eat, mate and finally die.

Before you start buying extra-strong facewash, you should know that these microscopic lodgers probably aren’t a serious problem. They may well be almost entirely harmless. What’s more, because they are so common they could help reveal our history in unparalleled detail.

There are two species of mite that live on your face: Demodex folliculorum and D. brevis.

They are arthropods, the group that includes jointed-legged animals such as insects and crabs. Being mites, their closest relatives are spiders and ticks.

Scientists have known that humans carry face mites for a long time

Demodex mites have eight short and stubby legs near their heads. Their bodies are elongated, almost worm-like. Under a microscope, they look as though they’re swimming through oil, neither very far, nor very fast.

The two species live in slightly different places. D. folliculorum resides in pores and hair follicles, while D. brevis prefers to settle deeper, in your oily sebaceous glands.

Compared with other parts of your body, your face has larger pores and more numerous sebaceous glands, which may explain why the mites tend to live there. But they have also been found elsewhere, including the genital area and on breasts.

Scientists have known that humans carry face mites for a long time. D. folliculorum was spotted in human earwax in France in 1842.

You may have around two mites per eyelash

In 2014, it became clear just how ubiquitous they are. Megan Thoemmes of North Carolina State University in Raleigh and her colleagues found, as had previous studies, that about 14% of people had visible mites. But they also found Demodex DNA on every single face they tested.

That suggests we all have them, and probably in quite large numbers. “It’s hard to speculate or quantify but a low population would be maybe in the hundreds,” says Thoemmes. “A high mite population would be thousands.” Put another way, you may have around two mites per eyelash.

The populations may well vary from person to person, so you might have many more than your neighbour or far fewer. You may also have more mites on one side of your face than the other.

Yet it’s not clear what the mites are getting from us. For starters, we’re not sure what they eat.

“Some people think they eat the bacteria that are associated with the skin,” says Thoemmes. “Some think they eat the dead skin cells. Some think they’re eating the oil from the sebaceous gland.”

They’ve never been known to eat one another

Thoemmes and her colleagues are currently looking at the microorganisms that live in the mites’ guts. That could help determine their diet.

We also don’t know much about how they reproduce. Other species of mite get up to all sorts of things, from incest and sexual cannibalism to matricide and fratricide. But so far it seems Demodex are a little less extreme.

“They’ve never been known to eat one another,” says Thoemmes. “It appears that they come out at night to mate and then go back to their pores.”

The only thing we know about is their eggs.

“We have caught a Demodex laying an egg on camera,” says Thoemmes. The video is available on YouTube.

These mites don’t have anuses

Female Demodex mites lay their eggs around the rim of the pore they are living in. But they probably don’t lay many.

“Their eggs are quite large, a third to a half the size of their body, which would be very metabolically demanding,” says Thoemmes. “They’re so large they’re probably laying one at a time, as I can’t imagine that more than one can fit in their bodies based on the size.”

Speaking of objects that Demodex need to push out of their bodies, these mites also don’t have anuses.

They still need to poo, so it’s been said that they ‘explode’ with waste at the end of their lives. However, that’s “a bit of an over-exaggeration”, says Thoemmes.

All their waste builds up over time and then there’s one large flush of bacteria

They do save it all up until death, though. When a Demodex dies, its body dries out and all the built-up waste degrades on your face.

“It’s not an exploding action necessarily, but it’s true that all their waste builds up over time and then there’s one large flush of bacteria,” says Thoemmes. “It’s not just coming in discrete units over time, it’s a lot built up that comes out.”

That may sound terrible. But surprisingly, it looks as though these mites are not harmful.

“I would think that they’re not harming us in a way that’s detectable,” says Thoemmes. “If we were having a strong negative response to their presence, we’d be seeing that in a greater number of people.”

People suffering from rosacea tend to have more Demodex mites

The one thing they have been linked to is a skin problem called rosacea. This mainly affects people’s faces, and begins with flushing before sometimes progressing to permanent redness, spots, and sensations of burning or stinting.

Studies have found that people suffering from rosacea tend to have more Demodex mites. Instead of 1 or 2 per square centimetre of skin, the number rises to 10 to 20.

But that doesn’t mean the mites cause the problem.

“The mites are involved in rosacea, but they’re not causing it, “says Kevin Kavanagh of Maynooth University in Ireland. In a study published in 2012, he concluded that the root cause was changes in people’s skin.

Our skin gradually changes over the years, for instance due to ageing or exposure to the weather. This alters the sebum, an oily substance produced by the sebaceous glands that helps keep our skin moist.

When the mites die, they release their internal contents

Demodex are thought to eat the sebum, and the change in its makeup may cause a population boom. “This causes irritation in the face, just because there are so many mites around,” says Kavanagh.

There also seems to be a link between rosacea symptoms and the big flush of bacteria released when a mite dies.

“When the mites die, they release their internal contents,” says Kavanagh. “This contains a lot of bacteria and toxins that cause irritation and inflammation.”

There may also be a link with the immune system, which normally protects us against infections. Thoemmes says the mites have been found to be particularly abundant on people with immune deficiencies, such as AIDS or cancer.

“I think mites are exploding because you’re having an immune response to something else,” she says. “Rosacea is another response to that.”

For most people, most of the time, they’re harmless

It’s still not clear what sort of relationship we have with our Demodex mites. We can be sure they are not parasites, which take things from us and cause harm in the process.

The relationship might instead be commensal, meaning that they do take something from us but not in a way that normally causes harm. For most people, most of the time, they’re harmless.

They may even be beneficial. For instance, they may clear dead skin off our faces or eat harmful skin bacteria.

But suppose you really wanted to get rid of them. Could you?

Although there are therapies that kill Demodex mites, we can’t get rid of them forever.

They rebound after about six weeks, says Kavanagh. “We pick them up from people who we are in contact with. We pick them up from sheets, pillows, towels. There’s good evidence that we transmit them between each other.”

We may pick up Demodex very early in life

It looks as if there is something special on our faces that they need. Even if you kill them off, you’re going to get them again, because they’re everywhere and they want to be on your face.

In line with that we may pick up Demodex very early in life. “Demodex mites have been found in mammary tissue,” says Thoemmes. As a result, she suspects they travel from mother to baby, perhaps through breast-feeding or even at birth.

We may then pick up a few more from the people we know as we grow older. Thoemmes’s study found more mite activity on adults over 18 than on 18-year-olds.

It also seems our species has carried Demodex mites for a long time.

Humans have long had a close relationship with domestic dogs

Thoemmes speculates it might be “since we evolved from our hominid ancestors”. That would mean we’ve been carrying these animals for 20,000 years.

We might have picked them up from other animals. D. brevis is particularly similar to a species that lives on dogs. Humans have long had a close relationship with domestic dogs, and with their wild relatives, wolves. Thoemmes suggests our ancestors “lived closely with them, for hunting purposes or that kind of thing”, and picked up the mites as a result.

As well as our relationships with animals, the mites could reveal a lot about our relationships with each other. Their genes contain clues to our history.

When Thoemmes looked at the mites’ DNA, she found that mites collected from Chinese populations were distinctly different from those collected from North and South American populations.

Because these differences exist, studying the mites could tell us how our distant ancestors migrated around the planet, and reveal which modern populations are most closely related.

“We might be able to figure out human associations… we weren’t able to figure out or see before,” says Thoemmes.

She is particularly interested in finding out about the colonisation of Central and South America. “There’s been a lot of speculation as to which populations of humans colonised Brazil and inter-bred,” she says.

Demodex could also allow us to peer much further back in time, and investigate how we evolved. If they’ve lived with us for so long, it is possible our immune systems have changed as a result. These little mites may have helped shape how we respond to disease.

Our bodies are seething with microorganisms

“They most certainly have an effect on us, as we do on them,” says Thoemmes. “We could be having immune responses to them, which could have been having an effect on our health and immune systems.”

For now, this is all speculation. But even if none of these ideas pay off, the story of Demodex is a reminder that we humans are home to a multitude of species.

Some, such as head lice and fleas, hop aboard occasionally, or only live on certain populations. Others, like Demodex and the microorganisms in our guts, are with all of us throughout our lives. Our bodies are seething with microorganisms: they make up 90% of our cells.

There is a simple lesson here. You are not just you: you are a walking, talking community, an entire ecosystem held within one body.

Demodex treatment options

Ophthalmologists are just beginning to understand how the mite causes recurrent inflammation to eyelids

A species of Demodex on a patient’s eyelashes

Demodex furrowing into the eyelid of a patient

A patient with mild Demodex infestation on the lids Source: Steven Safran, M.D.

Call it “The Case of the Mighty Mite.” For decades, refractory blepharitis has confounded ophthalmologists. Some patients respond to lid scrubs; some do not. Some present within days of a spouse’s presentation. Some present concurrently with pterygia. Blepharitis seems more pronounced in some than in others. The cause of blepharitis may be as simple as the Demodex mite. A recent journal article noted a variety of pathologic features together with conjunctival inflammation can be found in patients with Demodex infestation of the eyelids.1 These same kinds of pathologies are commonly found in ocular rosacea, said Scheffer C.G. Tseng, M.D., director of the Ocular Surface Center and medical director, Ocular Surface Research & Education Foundation at TissueTech, Miami. “When conventional treatments for rosacea fail, tea tree oil lid scrubs seem to eradicate the mites,” Dr. Tseng said. “In any type of ocular inflammation where the condition is refractory, doctors need to consider Demodex as a causative agent,” he said. “For instance, recurrent pterygia may be the result of an inflammatory disease, and it may be Demodex that hasn’t been well treated. That would explain the pterygia’s recurrence.”

Identifying symptoms of Demodex

Early morning itching and irritation is common with these mites because of their aversion to light, Dr. Safran said. “They come out at night and mate, lay their eggs on the lashes, and then crawl back into the follicle in the morning, causing the patient to itch,” he said. What makes the diagnosis of Demodex difficult is that some patients will have “a lot of Demodex, but no symptoms. I leave those people alone,” Dr. Safran said. “Other people have what appears to be an allergy to the mites causing severe itching and inflammation. These are the blepharitis patients that respond to Patanol (olapatadine, Alcon, Fort Worth, Texas), but it doesn’t cure them.”

In patients with facial rosacea, “the pathogenesis of skin lesions has been speculated to be caused by an increasing density of mites, which trigger inflammatory or specific immune reactions, mechanically block the hair follicle, or act as a vector to bring in bacteria,” Dr. Tseng said.

Tea tree oil treatment

Dr. Safran said Dr. Tseng’s identification of tea tree oil to treat the Demodex is novel, and he has slightly modified the formulation. While physicians can buy tea tree oil from most health food stores, Dr. Safran has also used an ointment Dr. Tseng is working on. If using the heath food store variety, he said to cut the oil to 50% in Macadamia nut oil. “I apply it with cotton tip applicators after one drop of tetracaine, so there’s no shield required,” he said. “I am very aggressive with trying to get the oil into the lash roots and along the lashes to kill any eggs. I also aggressively treat the eyebrows. I don’t like the applicator dripping wet, but it should be moist enough so I can see the oil getting onto the skin when it’s touched. I treat the brow first, then the lid to get rid of the excess oil where it won’t irritate as much. I’ll do three applications a visit, about 10 minutes apart, and then finish with a tea tree ointment at 20%, which I have mixed for me at a compounding pharmacy. I do this for three visits, each one week apart.”

Dr. Safran warned other physicians not to use full strength tea tree oil. “I tried that on myself, and it was not a pleasant experience,” he said. The patient must institute hygiene at home, he said, and that includes tea tree shampoo, scrubs and face wash.

Dr. Safran has patients follow this protocol: • use tea tree shampoo for the hair and eye lashes every day • use tea tree soap or face wash every day • women should throw out makeup and not use any new makeup for a week • clean sheets and/or buy new pillows • ensure the spouse is checked • have any pets that sleep on the bed checked • for the first few weeks, patients should use tea tree ointment at night after the shampoo scrub at home “If there’s a lot of inflammation, I like Tobradex (tobramycin 0.3% and dexamethasone 0.1% sterile ophthalmic suspension and ointment, Alcon) that’s replaced by bacitracin or erythromycin after one week,” Dr. Safran said. Anecdotal stories from Dr. Safran’s patients indicate that upon presentation, on a scale of 1 to 10, most patients stated, “Red eyes are associated with not feeling well, lack of sleep, those sorts of things. When their eyes burn and are red, patients are very aware of it. After they have the tea tree oil treatment, patients’ scores go from a 9 to a 2, or an 8 to a 1.”

Surprising asides

“A surprising finding was that once we got rid of the mites, some patients’ vision improved,” Dr. Tseng said. “Originally we thought this was a coincidence. Because mites affect the oil glands, the tear film is not doing well. If the tear film is unstable, it will cause a blur when the eye opens quickly. Once the mites are gone, the tear film stabilizes, and the vision improves.”

He did note that not all patients’ vision will improve; the fact that some did was a pleasant surprise. “The tea tree oil is probably not the last word on killing , but it’s better than anything else we have right now,” Dr. Safran said.

Editors’ note: Dr. Safran has no financial interests related to his comments. Dr. Tseng has filed a patent on the use of tea tree oil for ocular use.

CONTACT

Safran: 215-962-5177; [email protected]

Tseng: 305-274-1299; [email protected]

Eyelash extensions irritation: You probably don’t have lice, but you might have mites

Adrianna Rodriguez USA TODAY Published 12:41 PM EST Nov 24, 2019

If you use eyelash extensions and suffer from eye irritation, a buildup of microscopic organisms may be eating your skin.

Recent media reports have labeled these creatures eyelash lice, but doctors tell USA TODAY that they’re actually mites. And while mites live on all animals, eyelash extensions create risk for an irritating buildup of the tiny creatures.

Preventing the itching, redness and other symptoms associated with a mite buildup is simple: Establish a daily routine of washing around the eyes with warm, soapy water.

Washing is an important — often neglected — part of hygiene for people who wear false eyelashes. But the reports of a rise of eyelash lice are incorrect, doctors say.

Eyelash lice vs. mites

Dr. Gregory J. Nixon, Associate Dean for Clinical Services at the Ohio State University College of Optometry, say people are confusing the medical term demodex for lice, when they’re actually mites.

He adds that the confusion between the two organisms is problematic because it’s a very important distinction.

Lice are a parasites that suck blood and are usually the size of a poppy seed, according to Dr. Craig See, an ophthalmologist at Cleveland Clinic Cole Eye Institute. They can usually be seen by the naked eye, he said.

Mites, on the other hand, are microscopic organisms that that live on all mammals, See said. They don’t suck blood, but instead eat dead skin cells.

Lice can be transferred from one person to another, but Nixon doubts that they can be transmitted through fake eyelashes or eyelash extensions.

“Eyelash extensions are synthetic, it’s not natural,” he said. “The extensions are not transmitting anything or serving as a vector for people to get infected.”

See says that if lice were somehow transferred to the eyelashes, one would be able to see them. Lice cause irritation and require immediate treatment.

Nixon says mites don’t normally cause any issues. However, problems can arise if a buildup of mites is concentrated around the eye.

Head lice: Separating facts from fiction for your kids at school

What can I do to prevent a buildup?

Nixon says this is a common issue among people who practice poor hygiene and don’t wash around their eyes. A buildup of mites can cause itching, irritation, redness, scaling and flaking.

He says the best prevention method is to establish a daily routine of washing around the eyes with warm, soapy water. This helps break up the oils that fuel the mites.

Nixon says people who wear false lashes or eyelash extensions are more likely to neglect this daily routine.

“When you get eyelash extensions, a lot of patients neglect the normal hygiene that go into taking care of your normal eyelash,” Nixon said.

See says that irritation from false lashes or eyelash extensions is also commonly a result from the adhesive and usually goes away after the lashes are removed.

Scarring, ‘unbearable’ itching: Over 200 women sue prison over scabies outbreak

How can I treat a buildup of mites?

See recommended tea tree oil, which is available to patients over-the-counter, to treat an irritating buildup of mites. He says some patients can take some medications orally, but it’s pretty rare.

If anyone thinks they may be suffering from a severe infestation, Nixon urges them to see their optometrist for appropriate treatment.

He says that he hasn’t noticed an increase in these cases, but he’s glad there’s more awareness as it’s a common problem.

“Everybody knows to brush their teeth twice a day and don’t even think about it,” he said. “We know in the eye care field that your eyes are no different. A lot of patients don’t necessarily comprehend that.”

Follow Adrianna Rodriguez on Twitter: @AdriannaUSAT

Published 12:41 PM EST Nov 24, 2019

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“One can conclude that wherever mankind is found, hair follicle mites will be found and that the transfer mechanism is 100% effective! (One of my students noted it was undoubtedly the first invertebrate metazoan to visit the moon!)”

But it’s hard to say exactly how common they are. The first estimate came from a 1903 study, which found the critters in 49 out of 100 French cadavers. The next count, from 1908, found them in 97 out of 100 German cadavers. The nationalities are probably a red herring. What’s clearer is that age matters. The mites aren’t inherited at birth, so each generation picks them up anew, probably from direct contact with our parents. Thanks, parents! If you’re under 20, good news! A French study from 1972 says that you’ve only got a 4 percent chance of carrying Demodex. If you’re old, bad news! You’ve almost certainly got Demodex somewhere.

The mites spend most of their time buried head-down in our hair follicles – the stocking-shaped organs that enclose and produce our hairs. They’re most commonly found in our eyelids, nose, cheeks, forehead and chin. That’s not to say they’re restricted to the face: Demodex has been found in the hairs of the ear canal, nipple, groin, chest, forearm, penis, and butt too. Generally, dry skin is a turn-off for them. They prize bodily real estate that’s flooded with oils (sebum). This explains why they love your face. It might also explain why their numbers are apparently higher in the summer, when hot temperatures ramp up sebum production.

A mite-y existence

How do Demodex mites spend their time? They eat! Some say they eat sebum, but Nutting thought that such a diet wouldn’t be nutritious enough. Instead, he said that they feast on the cells that line the follicle, sucking out their innards with a retractable needle in the middle of a round mouth. On either side of the mouth, D.folliculorum has a seven-clawed organ (a “palpus”) for securing itself to what it’s eating. “All of the structures formed a sharp, offensive weapon,” writes Xu Jing, who first looked at them under an electron microscope. (D.brevis, with its five-clawed palpus, was branded as “less offensive”.)

They crawl! They move about in darkness and freeze in bright lights. The fact that mites have been found on the surface of the skin suggests that they emerge from follicles at night for shadowy strolls across our faces. With their stumpy legs, they’re hardly fast. It would take almost half a day for Demodex to cover the distance from your ear to your nose.*

They don’t poo! The mite has no anus, and stores its waste in large cells within its gut. Nutting saw these as adaptations for a life spent head-down in a tightly closed space. When the mite dies, its body disintegrates and the waste is released. More on this later.

And they have sex! On your face! Their favourite hook-up spots are the rims of your hair follicles. Males outnumber females by three to five times, but this detail aside, Demodex sex lacks much of the horror found throughout the arachnid clan. No traumatic insemination. No cannibalism. The penis and vulva are hidden within the pairs of legs. (Jing wrote that D.folliculorum’s penis “looks like a small candle when it was elongated”. He failed to see D.brevis’s.)

After sex, the female buries into the follicle (if it’s D.folliculorum), or into a nearby sebaceous gland (if it’s D.brevis). Half a day later, she lays her eggs. Two and a half days later, they hatch. The young mites take six days to reach adulthood, and they live for around five more. Their entire lives play out over the course of two weeks.

People with rosacea should look away now

Are they parasites, or something more benign? For the most part, it seems that they eat, crawl and mate on your face without harmful effects. They could help us by eating bacteria or other microbes in the follicles, although there’s little evidence for this. Their eggs, clawed legs, spiny mouthparts, and salivary enzymes could all provoke an immune response, but this generally doesn’t seem to happen.

But like many of our body’s microscopic residents, Demodex appears to be an opportunist, whose populations bloom to detrimental numbers when our defences are down. Several studies, for example, have found that they’re more common in people with HIV, children with leukaemia, or patients on immunosuppressive drugs. Perhaps changes to the environment of the skin also allow the mites to proliferate beyond their usual levels.

In dogs, an overabundance of D.canis can trigger a potentially lethal condition called demodectic mange, or demodicosis. In humans, these blooms have been linked to skin diseases like acne, rosacea and blepharitis (eyelid inflammation). The New Scientist piece will undoubtedly bring this to many people’s attention, but scientists have been talking about such connections for decades. The rosacea link was first put forward in 1925!

Dermatologists have since repeatedly found that Demodex is more common in the cheeks of people with rosacea. In one study, those with the condition had an average of 12.8 mites per square centimetre of skin, compared to 0.7 in unaffected people. And according to an analysis of 48 separate studies, people with rosacea are eight times more likely to have a Demodex infestation. Obviously, correlation not causation, blah blah blah, you know the drill.

There’s plenty of anecdotal evidence about mite-killing treatments and clinical improvements (here’s the latest involving tea-tree oil), but very little in the way of hard clinical trial evidence. An example: metronidazole is sometimes used to treat Demodex infestations, and there’s evidence from three clinical trials that it’s effective at treating rosacea (a Cochrane review, and everything!). Then again, Demodex can survive high concentrations of metronidazole, so maybe the mites are irrelevant to the substance’s actions.

In the new review, covered by New Scientist, Kevin Kavanagh suggests that rosacea may be caused not by the mites themselves, but by the bacteria in their faeces. After all, antibiotics that kill the bacteria, but are harmless to the mites, can sometimes successfully treat rosacea. But again: more correlations. The bacterial angle is fascinating, though. We know so little about these creatures that colonise our bodies, and now we must contend with our even greater ignorance of the creatures that colonise their bodies. Down the rabbit-hole we go!

And finally, if all of this sounds unbearably revolting, spare a thought for people with acarophobia – the fear of mites and other “small bugs that cause itching.” What words of solace can we offer to them? Here’s Nutting:

“Those patients with acarophobia (approximately 12 have been seen in our laboratory) seem curable if they follow a prescription which includes a relaxing vacation at the beach. If they insist on a follow-up examination for hair follicle mites, the situation is a bit delicate because most will still be positive. Diplomacy will prevail—only two of our 12 have failed to respond!”

Images: top photos from Nutting, 1976, HAIR FOLLICLE MITES (ACARI: DEMODICIDAE) OF MAN.

* One review I read quoted their speed at 16 centimetres per hour. Another said 16 millimetres. Given the stubby legs, the centimetre value surely cannot be right, so I’m going with millimetres.

Demodex

Demodicosis.

Demodectic mange is rare in the horse. Demodex caballi is commonly present in pilosebaceous units of eyelids and muzzle, generally without producing lesions. In contrast, Demodex equi is distributed over the body. Clinical lesions are rare, but when present, develop on the face, neck, shoulders, or forelimbs and consist of localized to diffuse alopecia and scaling or of papules, nodules, and pustules.

Demodicosis in cattle (Demodex bovis, Demodex tauri, and Demodex ghanaensis) and goats (Demodex caprae) is of little clinical significance, but extensive infection can damage hides by development of multifocal nodules in the skin of shoulders, neck, and face or in a more generalized distribution. Nodules correspond to follicular cysts that are filled with mites and keratinaceous material. Rupture of the cysts leads to severe granulomatous dermatitis and damage to the hide.

Sheep have two species of mites. Demodex ovis is located in hair follicles or sebaceous glands distributed over the body and can cause alopecia, erythema, scaling, pustules, and matted fleece. Lesions develop on the face, neck, shoulders, and back, but the ears, limbs, and coronary bands can also be affected. Demodex aries is located in sebaceous glands of the vulva, prepuce, and nostrils and can cause papular, rarely pustular, or nodular lesions.

Demodex phylloides of pigs causes scale-covered papules progressing to nodules that are filled with keratinaceous debris and mites and that damage the hide. Lesions develop in the ventral body skin, eyelids, and snout.

Demodicosis is one of the most common skin disorders of dogs in North America. Several different demodectic mites have been identified in dogs, D. canis (most common), Demodex injai (rare), and Demodex cornei (rare), a short-bodied mite. D. canis and D. injai live in hair follicles and can be found in sebaceous glands. D. cornei is found on the skin surface. Mixed infections with D. canis and D. injai and D. canis and D. cornei have been reported. D. injai has been associated with generalized demodicosis and a clinically greasy hair coat. D. cornei has been associated with generalized and localized demodicosis. Most cases of canine demodicosis are caused by D. canis, and occur in two clinical forms, localized and generalized, both of which are more common in juvenile dogs. Transmission from mother to offspring occurs via close skin contact, as occurs during suckling. Purebred dogs of many breeds are predisposed to infestation, suggesting an inherited basis for the disease related to a primary deficit in cell-mediated immunity. Research studies suggest the defect is one of T lymphocyte helper dysfunction, resulting in damage by cytotoxic T lymphocytes. Active lesions of demodicosis result in lymphocytic mural folliculitis with lymphocyte-mediated damage to the keratinocytes of the follicular wall. It is speculated that follicular keratinocytes express altered self-antigens or Demodex antigens, which leads to immune-mediated destruction of the follicular wall. Secondary immunodeficiency, caused by T lymphocyte suppression, is also associated with demodicosis, particularly if a secondary S. pseudintermedius infection is present. The secondary immunodeficiency improves as the demodicosis resolves. Results of studies conflict as to whether the secondary immunodeficiency is caused by the accompanying bacterial infection or the mite infestation. Demodicosis occurs in adult dogs with underlying metabolic disorders (hypothyroidism, hyperadrenocorticism) or that are given drugs (glucocorticoids or cytotoxic drugs) that can compromise the immune system. Idiopathic cases also occur.

Gross lesions of localized demodicosis in the dog consist of one to several small scaly, erythematous, alopecic, areas on the face or forelegs (see Fig. 17-26). Canine generalized demodicosis usually involves large areas of the body; lesions consist of larger coalescing patches of erythema, alopecia, comedones, scales, and crusts. The early microscopic lesions include epidermal hyperkeratosis, perifolliculitis, and lymphocytic interface mural folliculitis, including mild degeneration of follicular basal cells, follicular pigmentary incontinence, and intraluminal mites (see Fig. 17-26). Follicles can become plugged with large numbers of mites, keratin, and sebum. Secondary bacterial infection leads to neutrophilic folliculitis that in conjunction with mite proliferation and follicular hyperkeratosis progresses to follicular rupture. Mites, bacteria, keratin, and sebum spill into the dermis, stimulating a granulomatous to pyogranulomatous dermatitis. Perifollicular granulomas with portions of mites are often seen. Gross lesions in dogs with severe secondary bacterial infection include papules, pustules, edema, and draining sinuses. In severe demodicosis, inflammation and organisms spread into the subcutis, and lymphadenitis and septicemia can develop. Severe chronic lesions consist of dermal fibrosis with effacement of adnexal structures.

In cats, demodicosis is rare and is typically caused by two species of mites, one (D. cati) lives in follicles and sebaceous glands, and the other (D. gatoi) resides on the skin surface within the stratum corneum. A third species of demodectic mite in the cat (Demodex sp. unnamed) resembles, but is larger than, D. gatoi, but the significance of this mite has not been determined. Unless the immune response is compromised, lesions associated with D. cati are usually localized to the chin, eyelids, head, or neck. When the immune response is compromised, as in feline retroviral infections, generalized lesions of erythema, scaling, alopecia, pustules, and crusts develop. Histologically, cats with D. cati have epidermal and follicular hyperkeratosis and follicular atrophy. Inflammation is minimal. The most common sign associated with the presence of D. gatoi is pruritus, resulting in excessive grooming and symmetric alopecia. D. gatoi is contagious between cats, and there is an asymptomatic carrier state.

What are eye mites?

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