Belonging to the family Demodicidae and first described by Owen (1864) and Simon (1892), Demodex folliculorum is one of two species of microscopic mites now considered to be ubiquitously present on humans. Both mites, D.folliculorum and D.brevis, are host-specific obligate ectoparasites living respectively in the niche environments of hair follicles and sebaceous glands around the face and head. Generally their presence goes totally unnoticed but in some cases heavy infestations are believed to be the cause of certain forms of hair loss and such skin complaints as 'acne rosacea'.

Adult Demodex folliculorum on surface of skin x363

	For most of their existence the mites live head-down in a follicle feeding on secretions and general cell debris. An individual female may lay up to 25 eggs in a single follicle and as the mites develop they become tightly packed like cigars in a cigar drum. When mature, the mites vacate the follicle, mate and find a new follicle in which to lay their eggs. The whole cycle taking between 14 to 18 days.
Three D.folliculorum 'tails' protruding from a hair follicle x426
	A single infested hair follicle dissected away from surrounding tissue to reveal the heads of four inhabitants x277.   Just visible as specks to the unaided eye when viewed under ideal conditions, adults attain a length of up to 400um and about 45um at the widest part of the body.

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All images copyright © Andrew Syred 2001