Terminal hair

Terminal hair is a type of hair that is long, thick, and dark, as opposed to vellus hair, which is short, thin, and light. Terminal hair is found on the scalp, eyebrows, eyelashes, and, following puberty, on the underarms, pubic area, and face in both sexes. It also appears on the chest, back, and legs in males.

Development

The development of terminal hair involves the process of hair follicle maturation. During puberty, increased levels of androgens cause vellus hair to transform into terminal hair in certain parts of the body. The sequence of appearance of terminal hair follows a particular pattern known as the sexual maturation sequence.

Characteristics

Terminal hair is coarser and contains more melanin (the pigment responsible for hair color) than vellus hair. It is also longer and has a central medulla that is absent in vellus hair. The growth of terminal hair is influenced by several factors, including genetic predisposition, hormonal levels, and age.

Disorders

Several disorders can affect terminal hair, including hirsutism and hypertrichosis. Hirsutism is characterized by excessive growth of terminal hair in women in a male-like pattern, while hypertrichosis involves excessive hair growth over the body.

Treatment

Treatment for disorders of terminal hair growth often involves addressing the underlying cause. For example, in cases of hirsutism caused by polycystic ovary syndrome, treatment may involve hormonal therapy.

See also

• Hair follicle
• Vellus hair
• Androgenic hair
• Human hair growth