What term describes an abnormal excess of vellus-type hair, which may be darker than usual?

The term that describes an abnormal excess of vellus-type hair, which may present as darker than usual, is hypertrichosis. This condition can lead to the growth of hair in areas where it is not typically found, resulting in an increase of fine, soft hair typically associated with the vellus type. Hypertrichosis can occur congenitally (from birth) or can develop later in life due to various factors, including hormonal changes or certain medications.

In contrast, hirsutism specifically refers to excessive hair growth in women, typically where male-pattern hair would appear, such as the face and body, often due to hormonal imbalances. Alopecia refers to hair loss, not excess hair, and trichotillomania is a psychological disorder involving the compulsive urge to pull out one's own hair.

Understanding these definitions helps clarify why hypertrichosis is the correct term for the described condition of having an abnormal excess of vellus-type hair.