1. Department of Dermatology, Soonchunhyang University Cheonan Hospital, Cheonan, Korea.
2. Department of Dermatology, Soonchunhyang University Seoul Hospital, Seoul, Korea.
3. Department of Dermatology, Soonchunhyang University Bucheon Hospital, Bucheon, Korea.
4. Department of Preventive Medicine, Korea University College of Medicine, Seoul, Korea.