Differentiating generalized pustular psoriasis from acute generalized exanthematous pustulosis

To the Editor: Generalized pustular psoriasis (GPP) is a dermatologic emergency that is challenging to differentiate from other aseptic generalized pustular eruptions due to identical clinical and histopathologic findings, particularly those of acute generalized exanthematous pustulosis (AGEP). 1 Puig L. Choon S.E. Gottlieb A.B. et al. Generalized pustular psoriasis: a global Delphi consensus on clinical course, diagnosis, treatment goals and disease management. J Eur Acad Dermatol Venereol. 2023; 37: 737-752https://doi.org/10.1111/jdv.18851 Google Scholar ,2 Parisi R. Shah H. Navarini A.A. et al. Acute generalized exanthematous pustulosis: clinical features, differential diagnosis, and management. Am J Clin Dermatol. 2023; 24: 557-575https://doi.org/10.1007/s40257-023-00779-3 Google Scholar Although prognosis and treatment differ between the 2 diseases, no definitive features clearly distinguish GPP from AGEP. Therefore, we conducted a retrospective cohort study to compare the clinical and histopathologic features of GPP and AGEP in 2 geographic areas (United States and Japan) and developed a disease prediction scoring system.