This is excessive hair growth in an androgen dependent pattern. It is applied to females who complain of hair growth in the beard area, around the nipples and in a male pattern on the abdomen. It affects around 5-15% of women (1).
Typically hirsutism is caused by
- increased androgen production
- increased sensitivity of hair follicles to androgens (1)
Androgens induce the transformation of fine vellus hair (small, straight, and fair) into coarse terminal hair (larger, curlier, and darker and more visible). Some females with excess androgen may not have hirsutism but presents with seborrhea, acne or alopecia (2).
The condition is more common in dark haired individuals and in particular racial groups, such as women of Mediterranean origin. The psychological impact on the patient is often severe and many become depressed (1).
Hirsutism can be measured by using the "Ferriman-Gallway (mF-G) score". This is calculated by adding scores to nine body areas most sensitive to androgen from 0 (no hair) to 4 (frankly virile). A total score of >8 is considered to be an indication of hirsutism. There are some limitations to this scoring system due to the subjective nature of the evaluation (2).
Some females with excess androgen may not have hirsutism but presents with seborrhea, acne or alopecia (2).
This condition should not be confused with hypertrichosis - the growth of hair on any part of the body, in excess of the amount usually present in persons of the same age, race and sex (excess androgen is not the source) (2).