Abstract: 【Abstract】 Objective To analyze the effect of family history of female androgenetic alopecia （FAGA） and serum dihydrotestosterone （DHT） levels on the age at onset. Methods A retrospective analysis was conducted on 614 eligible patients newly diagnosed with confirmed FAGA at the Dermatology Hospital of Southern Medical University from November 2019 to January 2021, and 93 healthy controls were collected during the same period. Data on FAGA patients′ family history, serum DHT levels, age at onset, and duration of disease were analyzed, and differences in serum DHT levels were analyzed between the FAGA group and the control group. Results Among the 614 patients, the ages were 27.71 ± 6.11 years, the ages at onset were 25.25 ± 6.12 years, and the median duration of disease was 2.46 years; there were 231 patients （37.62%） with a positive family history and 192 （31.6%） with elevated DHT levels. Patients aged 20 - 30 years exhibited the highest DHT levels （310.19 ［238.98, 415.77］ pg/ml）, followed by those aged 31 - 40 years （273.24 ［193.85, 357.53］ pg/ml） and those aged 41 - 50 years （216.61 ［166.92, 289.98］ pg/ml）, and the difference was statistically significant （P < 0.05）. DHT levels were significantly higher in the patients aged 20 - 30 years than in the controls of the same age （298.55 ［218.19, 325.89］ pg/ml, Z = 2.39, P = 0.017）, and no significant differences in DHT levels were observed between the patients aged 31 - 40 years and their controls of the same age, nor between the patients aged 41 - 50 years and their controls of the same age （both P > 0.05）. The age at onset and age at consultation were significantly lower in the elevated DHT group than in the normal DHT group （both P < 0.001）, while the difference in disease duration was not statistically significant between the two groups （P = 0.350）. The age at onset was significantly lower in the patients with a family history （24.61 ± 5.90 years） than in those without （25.64 ± 6.22 years; t = 2.02, P = 0.044）, and the difference in DHT levels was not statistically significant between the two groups （Z = -0.52, P = 0.605）. Conclusions The serum DHT levels were higher in the FAGA patients aged 20 - 30 years than in healthy controls, but decreased to the normal level with age. No correlation was found between the family history and serum DHT levels, but the age at onset was earlier in the FAGA patients with a positive family history than in those without.

Key words: Alopecia, Femininity, Androgenic alopecia, Dihydrotestosterone