Gastrointestinal bleeding with severe mucosal involvement in a patient with generalized pustular psoriasis without IL36RN mutation

Generalized pustular psoriasis (GPP) is a systemic inflammatory disease that presents with erythema and sterile pustules, pathologically characterized by Kogoj's spongiform pustules. GPP is sometimes accompanied by mucosal involvement, and the most common lesion is on the tongue. IL36RN mutation was found to contribute to the pathogenesis of GPP especially in patients who develop GPP without a past medical history of psoriasis vulgaris. The association of IL36RN mutation with mucosal involvement in GPP is controversial. We herein report a 60-year-old male GPP patient with no past history of plaque psoriasis presenting with not only severe skin lesions and arthritis but also severe mucosal involvements of pharyngeal and gastrointestinal lesions, which led to gastrointestinal bleeding. Our case did not have any mutation in the IL36RN gene. We should be aware that severe GPP can cause gastrointestinal bleeding. The relevancy of IL36RN mutation with mucosal involvement in GPP remains to be elucidated.