Kun Li1, Linlin Xin2. 1. Department of Dermatology, Qianfoshan Hospital of Shandong Province, Shandong University, Jinan, Shandong, China; Shandong Academy of Medical Sciences, Jinan, Shandong, China. 2. Department of Dermatology, Qianfoshan Hospital of Shandong Province, Shandong University, Jinan, Shandong, China. Electronic address: Xinll158@sina.com.