X-linked inhibitor of apoptosis (XIAP) deficiency is a primary immunodeficiency associated with recurrent hemophagocytic lymphohistiocytosis (HLH) episodes. The clinical phenotypes of XIAP deficiency vary. ranging from splenomegaly to life-threatening inflammation. We report a case of XIAP deficiency with unusual late-onset HLH presentation likely triggered by a drug allergy. https://www.opheliasmuse.com/