What condition is characterized by an unusual amount of hair growth on normally downy parts of the body?

Hypertrichosis is the condition characterized by an unusual amount of hair growth on areas of the body that typically experience fine, downy hair. This excessive hair growth can affect both men and women and can occur in localized areas or be widespread across large parts of the body. It can be caused by genetic factors or may result from hormonal imbalances, medications, or certain medical conditions.

In contrast, alopecia refers to hair loss and does not involve increased hair growth. Hypotrichosis is a condition where there is an inadequate amount of hair, being the opposite of hypertrichosis. Trichotillomania is a psychological condition involving the compulsive act of pulling out one's hair, resulting in noticeable hair loss. Understanding these distinctions helps clarify why hypertrichosis is the correct answer in this context.