[Nevoid bundle hairs].

We report on two cases of naevoid bundle hair of the scalp. The clinical picture is characterized by an abnormal grouping of hairs emerging from one follicle ostium. The hairs arise from separate follicles but fuse into a common outer hair root sheath in the above the sebaceous gland. The outer hair root sheath is characterized by its abnormal reactivity with monoclonal antibodies against keratin but normal reactivity with anti-filaggrin. Naevoid bundle hair is thought to be an atavistic hair growth pattern.