A 66-year-old female patient suffering for 10 years from Crohn's disease firstly presented with a parallel outbreak of generalized pustulous psoriasis and Crohn's disease. A second synchronous exacerbation of both disorders occurred after discontinuation of treatment with prednisolone, methotrexate, and mesalazine. As to their pathogenetic concepts, both disease entities reveal similar immunologic alterations, i. e. comparable patterns of cytokines, chemokines, and inflammatory cells (T cells and neutrophils). Generalized pustulous psoriasis, therefore, might develop as hitherto undescribed, more rare extraintestinal manifestation of Crohn's disease.