Abstract: Lai Huiying, Lu Lingyi, Hou Xiaoxiao, Hu Tingting, Ju Qiang Department of Dermatology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China Corresponding author: Ju Qiang, Email: qiangju401@sina.com 【Abstract】 Objective To investigate the relationship between clinical types and related risk factors in female patients with post?adolescent acne. Methods Female outpatients with post?adolescent acne aged more than 25 years were enrolled from Department of Dermatology of Renji Hospital between January and October 2016. A questionnaire survey was conducted to investigate related risk factors for post?adolescent acne in the females. Skin lesions and clinical types were evaluated by dermatologists. Statistical analysis was carried out by t test for comparison of means between two groups and by chi?square test for comparison of ratios. Results A total of 312 female patients with post?adolescent acne completed the survey, including 268 （85.9%） with mild to moderate acne and 44 （14.1%） with severe acne, 241 （77.2%） with persistent acne and 71 （22.8%） with late?onset acne, or 102 （32.7%） with comedonal post?adolescent acne （CPAA） and 210 （67.3%） with papular post?adolescent acne （PPAA）. Survey on related risk factors showed that 121 patients reported seasonal factors and 59 （18.9%） patients became worse in summer, and spicy, sweet and fried foods can aggravate the condition in 131 （42%）, 93 （29.8%） and 85 （27.2%） patients respectively. Other risk factors such as premenstrual period （62.8%, 196/312）, psychological factors （51.6%, 161/312） and exogenous chemical exposures （43.6%, 136/312） were complained of by the patients. Furthermore, premenstrual period, diet and constipation were found to be more associated with PPAA compared with CPAA （χ2 = 4.523, 4.068, 3.910, respectively, all P < 0.05）. Exogenous chemical exposures, such as the use of cosmetics, exposure to polluted air environment and occupational hazards, were more associated with CPAA compared with PPAA, as well as with late?onset acne compared with persistent acne （χ2 = 6.579, 9.057, both P < 0.05）. In addition, premenstrual exacerbation occurred more frequently in patients with persistent acne compared with those with late?onset acne （χ2 = 4.512, P < 0.05）. Conclusions The risk factors for the occurrence of female post?adolescent acne are very complex. Premenstrual exacerbation plays a major role in the aggravation of papular and persistent post?adolescent acne, diet and constipation are more associated with PPAA, and exogenous chemical exposures are still be considered in the aggravation of comedonal and late?onset post?adolescent acne. Thus, clinical types should be considered in the diagnosis and treatment of post?adolescent acne in females.