Demodex folliculorum in hair follicles of eyelid skin.

Although Demodex folliculorum is a common inhabitant of eyelid hair follicles, it has received scant attention by ophthalmologists in recent years. I examined 100 biopsies of eyelid skin for the presence of these mites. The incidence of infestation increased with age; 84% of all cases and 100% of cases over age 70 years were involved. No organisms were seen in sebaceous or meibomian glands. I found no pathologic changes except for follicular distention and hyperkeratosis and occasional mild chronic perifolliculitis. Circumstantial evidence for incriminating Demodex in human disease is good, although scientific proof is lacking.