1. Department of Dermatology, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
2. Department of Dermatology, Uijeongbu St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
3. Department of Dermatology, Incheon St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
4. Department of Dermatology, St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
5. Department of Dermatology, Bucheon St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
6. Department of Dermatology, St. Vincent's Hospital, The Catholic University of Korea, Seoul, Korea.
7. Department of Statistics, The Catholic University of Korea, Seoul, Korea.