Journal of the European Academy of Dermatology and Venereology, 37(2), 395-401. Wiley-Blackwell Tzellos, T, van Straalen, K R, Kyrgidis, A, Alavi, A, Goldfarb, N, Gulliver, W, Jemec, G B E, Lowes, M A, Marzano, A V, Prens, E P, Sayed, C J, van der Zee, H H & Zouboulis, C C 2023, ' Development and validation of IHS4-55, an IHS4 dichotomous outcome to assess treatment effect for hidradenitis suppurativa ', Journal of the European Academy of Dermatology and Venereology, vol. 37, no. 2, pp. 395-401 . https://doi.org/10.1111/jdv.18632