Assessment of Serum and Tissue Estrogen to Androgen Ratio in Female Pattern Hair Loss

Background. Androgenetic alopecia (AGA) in males is known to originate via the conversion of circulating androgens into dihydrotestosterone DHT) by Sa-reductase enzyme within the hair follicles. Female patternhair loss (FPHL) is thought to be the female equivalent to male balding. The role of androgens and estrogensin women with hair loss remains unclear since most studies published about FPHL have failed to show androgen excess in all of the clinical types, and estrogen levels were repeatedly shown to be within normallimits. Objective. The aim of this study is to test if the estrogen to androgen ratio presented by the ratio of estradiol to free testosterone (E2/fT) and E2IDHEAS triggers FPHL in women; and also to study the ratio ofestrogen/androgen receptors in the scalp of women with FPHL in comparison to normal subjects. Patients and Methods. Twenty-eight premenstrual women with FPHL and a control group of 14 healthy women without hair loss were included in the study. Their serum levels of estradiol (E2), testosterone (free andtotal), SHBG, DHEA-S, LH and FSH were measured. Skin biopsies obtained from frontal and occipital scalp were stained immunohistochemically for androgen and estrogen receptors. Results. In patients the levels of estradiol (E2), the ratio of estradiol to free testosterone (E2/fT) and the ratio of estradiol to DHEAS(E2/DHEAS) were significantly lower than in the control group. In the scalp tissue, the estrogen/androgen receptor ratio in patients was decreased as compared to control group. Conclusion. We hypothesize that inthe presence of a genetic susceptibility, it is the estrogen to androgen ratio, as represented by the ratio of estradiol to free testosterone that might be responsible for triggering female pattern hair loss in women.