Female pattern hair loss, sebum excretion and the end-organ response to androgens.

Summary Background  Although female pattern hair loss can be a feature of hyperandrogenism, many women with hair loss show no clinical or biochemical features of androgen excess. It is possible that hair loss in nonhyperandrogenic women is due to a high level of response to androgens by scalp hair follicles. In this study we explored this idea using sebum excretion as a marker of the cutaneous end-organ response to androgens. Objectives  To test the hypothesis that hair loss in nonhyperandrogenic women is due to an increased cutaneous end-organ response to androgens. Methods  We studied 100 women, 41 with female pattern hair loss (without hirsutism), 29 with hirsutism (with and without scalp hair loss) and 30 subjects without hair problems. We measured hair density on the frontal scalp, forehead sebum excretion, serum free androgen index (FAI), and body mass index (BMI). Results  The mean FAI was significantly raised in hirsute women compared with nonhirsute women (P < 0·001), but there was no difference in FAI levels between nonhirsute women with and without hair loss. The mean BMI was also significantly elevated in hirsute women (P < 0·01) but there was no difference in BMI between nonhirsute women with and without hair loss. The mean sebum excretion was higher in hirsute women than nonhirsute women but the difference was not statistically significant. There was no difference in sebum excretion between nonhirsute women with and without hair loss. There was no correlation between hair density and sebum excretion. Conclusions  Our results show that sebum excretion is not elevated in women with female pattern hair loss. This may indicate that different androgen-response pathways operate in controlling hair growth and sebum excretion. The alternative explanation is that nonandrogenic mechanisms are involved in mediating hair loss in some women.