1. Department of Dermatology and Allergy; Interdisciplinary Mastocytosis Center Charité; Charité - Universitätsmedizin Berlin; Berlin Germany
2. Department of Dermatology; University of Lübeck; Lübeck Germany
3. Department of Dermatology; University of Cologne; Cologne Germany
4. Department of Dermatology; University Medical Center Mainz; Mainz Germany
5. Department of Dermatology; Clinical Center Darmstadt; Darmstadt Germany
6. Department of Medical Biostatistics; Universitätsklinikum Tübingen; Tübingen Germany
7. Laboratory of Allergic Diseases; National Institute of Allergy and Infectious Diseases; National Institutes of Health; Bethesda MD USA