Characteristics of the study population and the classification of need of treatment according to found skin disease.

*Pearson's Chi-Squared test or Fisher's Exact test.#Basic education (comprehensive schools), secondary level (upper secondary schools, vocational schools), tertiary level (universities, polytechnics).¤Skin findings which did not require treatment are excluded (for example benign skin tumors, androgenetic alopecia and erytematoteleangiectatic rosacea).*皮尔逊卡方检验（Pearson's Chi-Squared test）或费希尔精确检验（Fisher's Exact test）。#基础教育（综合中学）、中等教育（高级中学、职业学校）、高等教育（大学、理工学院）。¤无需治疗的皮肤病变已被排除（例如良性皮肤肿瘤、雄激素性脱发、红斑毛细血管扩张型玫瑰痤疮）。