Demodex Folliculorum

DEMODEX FOLLICULORUM, iron acne, small mites of the family Demodecidae with an elongated worm-like body (male 0.3 × 0.04 mm, female 0.38 × 0.04 mm) and 4 pairs of short three-segmented legs. The mouth parts are surrounded by a fold of skin—the epistome. The upper jaws are bristle-like, the lower jaws—two-segmented palps. It lives in the sebaceous glands of the face, ear canal, Meibomian glands of the eyelids and other places. Its entire development (egg, six-legged larva, two nymph stages and imago) can occur in the same hair follicle. Blockage of the latter, contamination and inflammation of the sebaceous gland favor the multiplication of D. f., which accumulates to 10-15 individuals in one gland, causing the formation of pustular pimples called acne. The parasites can be obtained from them by squeezing the contents of the pimple onto a slide. With massive infestation, a rash similar to impetigo contagiosa may appear on the skin. However, D. f. can live in healthy skin and not manifest its presence. Attempts have been made to establish a connection between D. f. with leprosy. Demodex folliculorum can transfer to domestic animals, e.g. to dogs and cows; in the former, its presence is associated with the manifestation of the action of Staph. pyogenes albus, and in the latter—with dermatosis caused by the bacterium Dermatophilus congolensis. Other species of D. are also known—D. canis, D. caprae, D. cuniculi, D. bovis, D. equi, etc.