Idiopathic Hypereosinophilic Syndrome With Cutaneous Manifestations: A Case Report

Hypereosinophilic syndrome (HES) is marked by eosinophilic infiltration and the release of inflammatory mediators that cause damage to multiple organs. Despite careful evaluation of hypereosinophilia, the etiology of most cases remains undefined. Eosinophils may cause damage in almost all organs, and most patients present with dermatological manifestations. We report a case of a 70-year-old man with a history of rheumatoid arthritis, who is under treatment with rituximab and leflunomide. He presented with generalized erythematous and pruritic cutaneous lesions that became scaly and hypopigmented, some of which were ulcerative and infected. Peripheral blood hypereosinophilia was noted (>6.0x10⁹ eosinophils/L). Primary and secondary causes of hypereosinophilia, including neoplasms and infections, were excluded, and idiopathic HES was assumed. The patient was started on oral prednisolone with complete resolution of the lesions.