What condition is commonly known as head lice?

Pediculosis is the medical term that refers to an infestation by lice, which are parasitic insects that feed on human blood. In this context, head lice specifically denote the presence of these parasites on the scalp and hair of the head. This condition is characterized by itching, irritation, and sometimes the presence of visible lice or their eggs (nits) adhered to the hair shafts.

The other conditions listed do not relate to head lice. Pilosis refers generally to hair growth and does not connote an infestation. Alopecia is a condition resulting in hair loss and is unrelated to lice. Scabies, while a skin condition caused by mites that results in severe itching, is distinct from lice infestation and affects the skin rather than the hair directly. Therefore, pediculosis is the accurate term for head lice infestation.