What is the medical term for the condition of excessive hair growth in unusual places?

The medical term for excessive hair growth in unusual places is hypertrichosis. It can affect a small, localized area or much of the body, and the excess hair may be fine vellus hair, soft lanugo-like hair, or coarser terminal hair.

Hypertrichosis may be congenital, meaning it is present from birth, or acquired later in life. Causes of acquired forms can include certain medications, nutritional or systemic illnesses, repeated irritation, and other medical conditions. Some inherited forms are extremely rare and have sometimes been sensationally described as “werewolf syndrome.”

Hypertrichosis is different from hirsutism. Hirsutism specifically refers to excessive terminal hair in women in androgen-sensitive areas such as the face, chest, or abdomen, often in association with hormonal conditions. Hypertrichosis is a broader term and does not require an androgen-related pattern.

The answer is also not trichotillomania, which is compulsive hair pulling, or alopecia, which means hair loss. The exact pattern, timing, and associated symptoms help clinicians determine the cause.