The presence of too much hair in body areas where normally hair is less compared with that of others of the same sex and age
Hirsutism refers to the presence of excess hair in body areas that have typically less hair. It is often associated with women growing hair in body areas similar to a male-type hair distribution pattern. It also often involves androgenic effects leading to the excessive hair growth. Thus, most cases of hirsutism manifest at puberty, together with other male-pattern pubertal changes such as deepening of the voice, acne, seborrhea, and palpable muscle mass. Females may also experience irregular menstrual periods. These changes are chiefly caused by an excessive androgen production.
Hirsutism manifests in females when they grow mustache and beard. Hair may also appear on the thorax, shoulders, back, arms, thighs, pubic triangle, and buttocks.1 At puberty, these secondary sexual characteristics typical in males appear in some females due to the overproduction of the hormone, androgen. In females, the androgen is produced by the ovaries and the adrenal glands. Overproduction of androgen is often associated with certain conditions such as polycystic ovarian syndrome, adrenal tumours, and the use of androgenic and anabolic steroids. Hirsutism may also occur due to an increased sensitivity to androgen despite the normal serum levels.
Congenital hirsutism also occurs when the excessive hair growth appears at birth. Most of the cases of congenital hirsutism involve genetic inheritance, and serves as one of the symptoms for particular disorders or syndromes.
1 Peytavi, U. (2008). Hair growth and disorders. Berlin: Springer. p.357-ff.