April 2008

 

OPHTHALMOLOGY NEWS

 

Demodex treatment options


by Michelle Dalton EyeWorld Contributing Editor

 

New treatment, old cause

Before Dr. Tseng and his colleagues tried the tea tree oil scrub, “there was no treatment that could kill the Demodex. You can clean the lashes and use the shampoo, but no agent could truly kill it. Tea tree oil does. That’s very major. If doctors can’t kill an organism, they don’t really know if the treatment is effective,” he said. To diagnose the problem, Steven Safran, M.D., said initially the diagnosis requires examining the lashes with a microscope to know what to identify. “[The mites] sit head down, tails up, with the tails aligned along the lash at the root,” Dr. Safran said. “Often there is columnar dandruff or cylindrical cuffing. If you rock the lash from side to side and pull, you’ll see the tails spread out along the base of the lash like little bristles. When you pull the lash, often the mites stay in the follicle, and you have to dip the lash back down into the follicle to get some of the mites onto the lash for evaluation.”

He said most patients are disbelieving at first, “until you show them the mites moving under the microscope. When they see that, they’re ready to listen.”

Dr. Safran stressed that epilating the lashes alone is not sufficient. “With many of the first patients I examined, I missed the mites because I was just pulling lashes and looking, which was quite ineffective in many patients,” he said.

 

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

A species of Demodex A species of Demodex on a patient’s eyelashes

Demodex

Demodex furrowing into the eyelid of a patient

Mild Demodex infestation

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 [Demodex], 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; safran12@comcast.net

Tseng: 305-274-1299; stseng@ocularsurface.com

References:

1. Kheirkhah A, Casas V, Li W, Raju VK, and Tseng SCG. Corneal manifestations of ocular Demodex infestation. Am J Ophthalmol. 2007;143:743-9.