Acne Incidence and Severity in Transgender Individuals

Importance Acne commonly affects transgender individuals prescribed gender-affirming hormone therapy, yet population-level incidence data remain limited. Objective To compare the incidence of acne and moderate to severe acne in transgender individuals, including those initiating gender-affirming hormone therapy, with matched cisgender individuals. Design, Setting, and Participants A retrospective matched cohort study of electronic health record data was carried out across 4 Kaiser Permanente health plan regions. Index dates were the earliest documentation of transgender status, ranging from January 2006 to February 2022, with up to 5 years of follow-up. Participants included individuals without baseline acne, transmasculine individuals, and transfeminine individuals matched with cisgender male and female individuals. Analyses were conducted from November 2024 to November 2025. Main Outcomes and Measures The primary outcome was incident acne (first acne-coded visit after the index date). The secondary outcome was moderate to severe acne (incident acne followed by prescription fill for isotretinoin or 30 or more days of oral antibiotics). Exploratory analyses compared acne care utilization by transgender status. Results Overall, 280 997 individuals without baseline acne, including 11 234 transmasculine and 9486 transfeminine individuals, were matched to 132 462 cisgender men and 127 815 cisgender women on age, self-reported race and ethnicity (25 340 Asian [9.0%]; 23 234 non-Hispanic Black [8.3%]; 56 876 Hispanic [20.2%]; 153 666 non-Hispanic White [54.7%]; 6989 other [2.5%]), enrollment year, and region. Of these, 12 156 transgender individuals initiated gender-affirming hormone therapy after the index date. The mean (SD) age at index date was 27.7 (10.0) years for transmasculine individuals and 33.2 (13.5) years for transfeminine individuals. Cumulative incidence of acne at 5 years was 15.8% in transmasculine individuals, 3.8% in matched cisgender male individuals, and 10.5% in matched cisgender female individuals and was 6.0% in transfeminine individuals, 2.9% in matched cisgender men, and 8.4% in matched cisgender women. Acne risk in transmasculine individuals was highest in the first year after testosterone initiation (vs matched cisgender male individuals: hazard ratio (HR), 8.29; 95% CI, 7.11-9.68; vs matched cisgender female individuals: HR, 2.63; 95% CI, 2.33-2.97) and remained higher in subsequent years than among cisgender men (HR, 5.29; 95% CI, 4.45-6.28) and cisgender women (HR, 1.69; 95% CI, 1.46-1.96). Acne risk was higher in transfeminine individuals after starting estradiol than cisgender men (HR, 1.56; 95% CI, 1.31-1.84) and lower than cisgender women (HR, 0.53; 95% CI, 0.46-0.62). Moderate to severe acne incidence followed similar patterns. Conclusions and Relevance This study revealed distinct acne incidence patterns in transgender individuals compared with matched cis male and female cohorts. Clinicians should monitor and treat acne in transmasculine individuals prescribed testosterone per clinical guidelines, particularly during the first year. Clinicians should also recognize that acne may develop in transfeminine individuals after estradiol initiation.