1. Department of Pediatrics, Chung-Ang University College of Medicine, Seoul, Korea.
2. Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea.
3. Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
4. Environmental Health Center for Atopic Diseases, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.