Ocular manifestations of Demodex infestation. (A) typical cylindrical dandruff at the root of the eyelashes (arrow); (B) misdirected lashes (arrow); (C) meibomian gland dysfunction (arrow); (D) lid margin inflammation (arrow); (E) bulbar conjunctiva inflammation; (F) corneal infiltration and pannus (arrow).
（Eyelid margin examination reveals inspissated glands (arrows) in meibomian gland dysfunction.）
A 25-year-old woman with Demodex. (All photos courtesy Steven Safran, MD.) -
An 11-year-old girl with Demodex before (left) and three months after treatment.
A 77-year-old with rosacea and Demodex.
A patient with Demodex blepharitis. Note the Demodex folliculorum mite coming off the lash.
Anterior Blepharitis affects the front part of the eyelid margin, near the roots of the eyelashes. It is commonly caused by bacteria that normally live on our skin, that produce an irritative toxin that causes inflammation. The lid margin often looks 'crusty' and when seen under a microscope, the appearance can be similar to dandruff. Anterior Blepharitis can cause the eyelids to become red, itchy and sometimes slightly swollen too.
Posterior Blepharitis is also referred to as Obstructive Meibomian Gland Disease. The meibomian glands are located within the eyelid, and the pores of the glands open onto the lid margin, behind the roots of the eyelashes. The glands normally produce a special oily secretion for the tears. The meibomian glands sometimes become inflamed and blocked, causing a reduction in amount, and disturbance in quality of the oily secretions. This can not only cause eyelid margin irritation, but also has secondary dry eye effects on the ocular surface.
Keratinization mixed with lipids produces the classical clear cylindrical dandruff that is associated with Demodex blepharitis.
The main symptoms of Demodex infestation are itching, burning, foreign body sensation, crusting and redness of the lid margin and blurry vision. Patients with Demodex infestation can have cylindrical dandruff, disorders of the eyelashes, lid margin inflammation, meibomian gland dysfunction, blepharoconjunctivitis and blepharokeratitis.
“Most Demodex are on the eyelid or on the skin around the eye,” Dr. Safran says. “You don’t necessarily see it until you know how to look for it. I’ve seen patients with very hot eyes with inflammation where I didn’t see Demodex on the eyelashes but I found it in the skin around the lid. You may not find it where you think you are going to find it. You can’t just pull lashes and say, ‘let’s count the Demodex.’ They live at the base of the lashes. In many patients, you will pull the lashes, and you won’t see the Demodex. You have to tease them out. I know how to find them at the slit-lamp, so I don’t have to look under a microscope. The reason I put the lashes under a microscope is to show patients what they have. Otherwise, they don’t necessarily understand it or believe you. They might go for a second opinion to someone who has not heard of this problem.” Fortunately, the number of ophthalmologists who are knowledgeable about Demodex infestation is on the rise. “Five years ago, if I told a patient that he or she had mites causing blepharitis and she went to a place like Wills or Hopkins, the possibility existed that the patient could be told that the doctor had ‘never heard of such a thing,’ ” says Dr. Safran. “Now, more people are aware of it. If you look at the dermatology literature, for example, there are many articles showing the association between rosacea and Demodex. We know that rosacea is associated with blepharitis. Rosacea is associated with Demodex, and blepharitis is associated with Demodex. It is pretty clear to me that there is a circle here where both rosacea and blepharitis are associated with Demodex. Demodex is probably at the root of a lot of these patients’ problems. When we treat their Demodex with systemic and topical medications, not just their eyes get better, but, in most cases, their rosacea vastly improves.”
According to Dr. Tseng, one reliable method of identifying Demodex is looking for cylindrical dandruff. “Some patients may not present with cylindrical dandruff, but they may have mites. The most reliable method to diagnose Demodex is the sampling of the lashes and looking at them under the microscope,” Dr. Tseng adds.
Two Demodex attached to the hair follicle root.
A single dead mite. Note the legs sticking straight out.
Two views of multiple mites coming from a collarette, and a single mite on the follicle.
Multiple mites coming from a collarette.
The good news is that the lifespan of the Demodex mite is short (approximately 19 to 23 days). The bad news is that they mate and continue to grow in number if you don’t remove them all.
“If you have an effective means to prevent them from mating through hygiene, then the population will be under control and eventually eradicated,” Dr. Tseng says. “The problem is that the eye socket, as I said, is not an area where hygiene is routinely practiced, so the mites tend to flourish in numbers. Once they get out of control, they cause blepharitis.”
A number of treatment regimens have been used in an attempt to control Demodex mite infestation; however, the adult Demodex folliculorum mite is resistant to many common antiseptic solutions. “Based on the knowledge we have, the first treatment is hygiene,” Dr. Tseng says. “We have some general instructions that we ask people to follow. First is total body cleaning with regular shampoo or soap, not just the eye but the whole body because mites can spread from one territory to another. In terms of the environment, such as the bedding, it is probably good to routinely wash the bedding at least once a week and put it through a hot dryer so that the mites can be killed. Pets can have their own mites. Whether the mites can move from pets to humans remains unclear, so it may not be a good idea to sleep with pets.”
Lid scrub with tea tree oil has been found to clean dandruff from the lash root and also to stimulate embedded mites to migrate out of the skin. Typically, a daily lid scrub with 50% tea tree oil and lid massage with 5% tea tree oil ointment will resolve ocular Demodex infestation.
“Specifically for the eye, there are a lot of so-called lid scrub cleansing agents on the market that are over-the-counter,” Dr. Tseng says. “We haven’t found them to be effective in killing mites. We use 75% alcohol to clean our hands or sterilize our instruments before surgery, but even that won’t kill mites. We continued to search for a natural yet effective solution and found tea tree oil as a potential killing agent. A few years ago, we received an NIH research grant to further determine the active component in the tea tree oil. We are now formulating the active component into a single-use, disposable cleansing pad called Cliradex, which will be commercially available in the next few months.” (Dr. Tseng is the inventor and patent holder of the product.)
Cliradex is a two-part system that includes a cleansing eyelash scrub and a cleansing skin cream. The scrub is used to stimulate the mites out from deep skin and cause direct killing, and the cream prevents the mites from mating.
According to Dr. Safran, in addition to tea tree oil, permethrin and ivermectin can be used as treatment. “We don’t have the world’s greatest treatments for this,” he says. “Right now, as a topical treatment, we use tea tree oil as the mainstay of treatment. We treat deep into the patients’ lashes and into the skin around the lashes and the brows every four to five days. We train the patients to treat themselves so they can maintain the process. Sometimes, we need a steroid to quiet things down. We’ll use topical permethrin 5% to the whole facial area around the eyelids every four days or so. We also use oral ivermectin, which has been shown to be helpful. I started using that based on the veterinary literature. Often, the veterinarians get first crack at a medication that has human application, such as was the case with topical cyclosporine for dry eye. Veterinarians use ivermectin to treat demodectic mange. Not every dog that is exposed to Demodex ends up with mange. There is a variable host response, and that is something that we see in humans as well.”
A recent study conducted in Brazil found that oral ivermectin effectively reduced the number of Demodex folliculorum found in the lashes of patients with refractory blepharitis. This study included 24 eyes of 12 patients with refractory posterior blepharitis with Demodex folliculorum in the lash samples. Patients were given one dose of oral ivermectin (200 µg/kg) and were told to repeat the treatment after seven days. After treatment, fewer Demodex folliculorum were found in the lashes, and average values of Schirmer I test results and tear breakup time improved.
As mentioned earlier with regard to patients’ bedding, heat effectively kills Demodex. Dr. Safran is currently evaluating radiofrequency and heat as potential treatments. “I’m currently exploring using the Pelleve radiofrequency system off-label to treat blepharitis/Demodex,” he says. [The manufacturer] Ellman made special hand pieces for me so that I can treat patients right up to the lid margin and try to kill Demodex with radiofrequency energy/heat. I’m not crazy about treating patients with tea tree oil. It’s messy, it’s smelly and it stings. I don’t think it’s the best way to kill these things, but it’s the best way we have. If you don’t stay on top of it, ultimately, they come right back,” he says.
The importance of hygiene cannot be overemphasized. “Patients have to shampoo their hair. Many little old ladies go to the beauty salon once every week or two and get their hair done and then shellacked in place,” Dr. Safran adds. “You are not going to get rid of Demodex if you can’t get them to shampoo their hair. We give them tea tree oil shampoo, and if they refuse to use that, there is nothing I can do for them. You can’t just treat the lid because they will come right back.”
BlephEx™, the newest treatment for blepharitis, is an in-practice procedure performed directly by the optometrist. With BlephEx™ the clinician thoroughly and precisely eliminates the scurf and bacterial debris, the main causes of inflammatory lid disease.
A treated eyelash.
1.Blepharitis Diagnosis: Don’t Forget Demodex
2.What is Blepharitis?
4.Demodex infestation requires immediate, aggressive treatment by doctor, patient
5.Eyelash Mites Symptoms, Treatment of Demodex, Facial or Mites on Eyelashes
6.Managing Blepharitis: Tried-and-True and New Approaches