Effects of hormonal treatment on dermatological outcome in transgender people: a multicentric prospective study (ENIGI).

PURPOSE: The aim of our study was to assess dermatological changes in transgender people after the start of gender-affirming hormonal treatment (GAHT) and to investigate whether various hormonal preparations differently affect dermatological changes in trans AFAB (assigned female at birth) people. METHODS: In a multicenter prospective study, 484 participants (193 assigned male at birth/AMAB and 291 AFAB) were evaluated at baseline (T0), 6 (T1) and 12 months (T2) after the start of GAHT. Hair growth was assessed by the Ferriman-Gallwey (FG) score, acne by the Global Acne Grading Scale (GAGS), and alopecia by the Norwood Hamilton (NH) score. RESULTS: In AFAB people, a significant increase in FG score and NH grade was observed across time, as well as in GAGS score in a subsample of 71 individuals (p < 0.001). Testosterone (T) undecanoate and esters showed a higher increase in hair distribution at T2 vs. T1 as compared to T gel (p < 0.01). T esters showed a significantly higher impact in GAGS score modifications at T1 and at T2 vs. T0 compared to T gel (p = 0.021 and p = 0.003, respectively). In trans AMAB people, a significant decrease of FG score was observed across time (p < 0.001), although 51.3% of individuals still reported an FG score higher than eight after 12 months. CONCLUSION: T treatment increased hair growth, acne and alopecia prevalence in AFAB people, with T undecanoate and esters influencing hair growth more than T gel. Opposite dermatological changes were observed in AMAB people.