Eyelash mite tails (green) protruding from a hair follicle, coloured scanning electron micrograph (SEM). The hair shaft (yellow) is also seen. Eyelash mites are harmless parasites that infest hair follicles around the eyelids, nose and in the ear canals of humans. They feed on oily secretions from the skin's sebaceous glands, as well as dead skin cells. Infestation is usually symptomless, but in some individuals, allergic reactions to the mites can cause hair loss and acne. Two species living on humans have been identified: Demodex folliculorum and Demodex brevis. Magnification: x400 when printed 10 centimetres wide.