1 Department of Dermatology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pa.
2 Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, Md.
3 Department of Dermatology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pa; Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pa. Electronic address: joel.gelfand@pennmedicine.upenn.edu.