Which parasite (mite) infection is known to target hair follicles and sebaceous glands including the meibomian glands?

• A. Sarcoptes scabiei
• B. Pediculus humanus capitis
• C. Demodex
• D. Ixodes scapularis

Answer: (C)

Some mites specialize in living in the skin’s oil-producing and hair-supporting units. Demodex species inhabit hair follicles and sebaceous glands, and on the eyelids they are found in lash follicles and the meibomian glands. This localization explains ocular symptoms like blepharitis and lash crusting, since the mites thrive in the pilosebaceous unit of the eyelids.

In contrast, the other organisms act in different skin niches: scabies mites burrow in the epidermis rather than pilosebaceous units; head lice live on hair shafts and feed on blood on the scalp; ticks attach to the skin but are not mites of the pilosebaceous apparatus. Thus, the parasite known to target hair follicles and sebaceous glands, including the meibomian glands, is Demodex.