Alopecia refers to which of the following conditions?

Alopecia is a medical term that specifically refers to hair loss. This condition can manifest in various forms, including patchy hair loss known as alopecia areata, and it can affect both the scalp and other areas of the body where hair grows. It is important to recognize that alopecia can be caused by a variety of factors, including genetic predisposition, autoimmune responses, hormonal changes, and certain medical treatments.

The other conditions listed involve different issues altogether: excessive body hair refers to hypertrichosis, dry, white flakes from the scalp describe dandruff or seborrheic dermatitis, and an infestation with lice is known as pediculosis. Each of these conditions has distinct characteristics and causes that differentiate them from alopecia. Understanding the definition of alopecia as related specifically to hair loss helps clarify its clinical significance and the various implications it may have on an individual's health and well-being.