Aromatase inhibitors induce 'male pattern hair loss' in women?

Female androgenetic alopecia (FAGA) is a common and distressing cause of hair loss, caused by androgens in genetically susceptible women [1, 2], in which dihydrotestosterone (DHT) binds to androgen receptors leading to miniaturization of scalp hair follicles [3]. FAGA, characterized by a specific diffuse loss of hair of the parietal or frontovertical regions ('in the crown'), where 5α-reductase is expressed, maintains the frontal hairline, where aromatase is localized, with a uniform miniaturization of hair from centroparietal regions causing diffuse alopecia of oval form that is surrounded by a circular band of hair, with normal density [4, 5]. We studied 15 menopausal women aged from 50 to 60 years, with hormone receptor-positive breast cancer, between the ages 50 and 65 years, receiving aromatase inhibitors (AIs), anastrazole or letrozole, according to the American Society of Clinical Oncology guidelines. After 1 year of therapy, they had hair loss and were not subjected to any other therapies and currently they are still subjected to AIs therapy. We observed hair findings by Global photo and videodermoscopic assessment, after 12(T0) and 24 months (T24) of anastrazole therapy. Evaluation of alopecia was carried out for each patient, with a score (from −3 to +3), derived by a comparison of the global photos taken at the beginning (T0) and at T24 (20–70× Trichoscan Dermoscope Fotofinder®). Recession of the frontal and parietal hairlines and diffuse hair loss (Figure 1a and b) were observed. Miniaturization of follicles in the fronto-temporal area (Figure 1c) was revealed. Behind the scalp area sensible to aromatase, in the frontal region, the diameter of hair was normal without any alterations, with normal hair density (Figure 1d). Aromatase (P450arom) is an enzyme located in outer root sheath, converting androstenedione to estrone and testosterone to estradiol, decreasing testosterone and DHT levels [2]. Levels of p-450arom in frontal and occipital follicles of women are Figure 1. (a and b) Recession of the frontal and parietal hairlines and bitemporal gulfs recession observed by Global photo; (c)miniaturization of follicles in the fronto-temporal area, observed by videodermatoscopic examination,which is not present in FAGA; (d) behind the frontal region, normal hair density and normal diameter of hair, evidenced by videodermatoscopic examination.