Reducing ocular Demodex using petroleum jelly may alleviate dry eye syndrome, blepharitis, facial dermatoses, ocular and respiratory allergies, and decrease associated prescribing: a hypothesis

Abstract

Demodex eyelash mites are increasingly associated with eye and skin inflammation in humans, and cause demodectic mange in mammals. Informal accounts of symptom improvement and reduced need for anti-allergy medicines, when Demodex reproduction is prevented, indicate a further role linking Demodex to rhinitis, asthma and dermatitis. Their mobility, allergenic debris and consequential immunological impact may also explain progression of allergies in the "allergic march". Being photophobic and nocturnal, Demodex folliculorum shelter, feed, and sleep in eyelash follicles during daylight. Coston (1967) speculated that Demodex emerge to mate during darkness and observed that medicated ointments rubbed into the eyelid margins at bedtime treated Demodex blepharitis effectively, presumably by preventing mating. Sixteen cases are described retrospectively whereby interested volunteers adopted Coston's technique, using unmedicated petroleum jelly. To break the lifecycle, a minimum 28-day course was advised, though concordance varied. Fourteen people reported relief from a surprising range of symptoms including not only dry eye and blepharitis but also rhinitis, asthma, angioedema and seborrhoeic dermatitis. Analysis of GP prescribing data in three volunteers allowed comparison of five-year periods immediately before and after starting continuous treatment. Mean yearly issues of anti-allergy and antimicrobial medicines reduced from 15.6 (range 8-25) to 1.8 (range 0-4), representing an 88.5% decrease for Volunteer 1 and from 5.8 (range 3-9) and 14.2 issues (range 9-24) to zero for both Volunteer 2 and Volunteer 13 respectively, representing 100% reductions in prescribing. Exacerbations of acne and dermatitis in two cases illustrate possible Demodex involvement in common dermatoses. This account is limited by its informal and retrospective nature in a disparate cohort, without assessment of Demodex levels. These preliminary observations support the hypothesis that Demodex allergens may trigger facial, ocular and respiratory inflammation and that reducing mite count with petroleum jelly improves symptoms. Formal clinical trials are needed to test this hypothesis.

Keywords: Demodex; allergy; asthma; blepharitis; dermatitis; petroleum jelly; prescribing; rhinitis.

Figure 1

Scanning electron micrograph of an adult Demodex folliculorum. ©Power & Syred, Science Photo Library.

Figure 2

Scanning electron micrograph showing Demodex tails protruding from a hair follicle. ©Power & Syred, Science Photo Library.

Figure 3

Scanning electron micrograph of a sebaceous gland from a dog, showing heavy Demodex infestation © Eye of science, science photo library.

Figure 4

Graphs to show the impact of the Coston technique on the number of allergy-related items issued by the GP for Volunteers 1, 2 and 13 for the years for which data were available. Years of birth for V1, V2 and V13 were 1928, 2000 and 1997 respectively. (A) Effect of Coston treatment, using petroleum jelly, on allergy-related GP prescriptions issued, by indication, for Volunteer 1. (B) Effect of Coston treatment, using petroleum jelly, on allergy-related GP prescriptions issued, by indication, for Volunteer 2. (C) Effect of Coston treatment, using petroleum jelly, on allergy-related GP prescriptions issued, by indication, for Volunteer 13.