When treating blepharitis patients, ophthalmologists should look very carefully for signs of infestation by tiny Demodex mites, which studies have found to be concomitant with 42% to 81% of blepharitis cases, Christine Shieh, MD, told Cornea Subspecialty Day attendees on Saturday.
And if the signs of demodicosis are there: “Smite the mite!” advised Dr. Shieh.
Diagnostic clues. The characteristic diagnostic signs of mite-related blepharitis are “collarettes” of waxy, cylindrical dandruff at the base of the eyelashes—an indicator of Demodex folliculorum residing and feeding inside the hair follicles. A smaller mite, D. brevis, infests the meibomian and sebaceous glands, where they can cause inflammation, Dr. Shieh said.
Management. Clinicians currently lack a definitive cure for Demodex blepharitis, and most of the available data relate to the use of tea-tree oil or terpinen-4-ol, in combination with eyelid hygiene, she said. However, there is increasing interest in off-label usage of antiparasitic medications that have been approved for dermatologic use, Dr. Shieh said.
Researchers have reported positive results with a topical rosacea remedy, ivermectin 1% cream (Soolantra, Galderma), sometimes combined with metronidazole, and with oral ivermectin. There is also a Demodex blepharitis case series on the off-label use of permethrin 5% cream (which is FDA labeled for use against scabies), she said.
Meanwhile, Dr. Shieh noted that the first FDA-approved medication to treat Demodex might be around the corner. Tarsus Pharmaceuticals reported in July on positive results in a controlled phase 2b/3 clinical trial of its TP-03 medication (lotilaner 0.25% solution) in patients with Demodex-related blepharitis.
After four weeks of daily topical therapy, patients treated with lotilaner had statistically significant and clinically meaningful reductions in mite numbers and lid erythema, trial researchers reported. Tarsus expects to release results from its 421-person, phase 3 efficacy trial in early 2022. —Linda Roach
Financial disclosures: Dr. Shieh: None.