Idiopathic hypereosinophilic syndrome: a report of four cases in Arabs, and a review of the literature.

We report four Arab patients with idiopathic hypereosinophilic syndrome (IHES). They presented with varied clinical pictures simulating chronic inflammatory bowel disease (IBD), pulmonary tuberculosis (TB), meningioma, peripheral neuropathy, and infective endocarditis (IE). All had significant peripheral and bone marrow eosinophilia, histological confirmation of eosinophilic infiltration of multiple organs, and clinical evidence of multi-organ dysfunction. Extensive laboratory investigations excluded other possible causes of eosinophilia. All were treated with steroids, with complete response in two. Two others were treated additionally with hydroxyurea, and one with methotrexate, cyclophosphamide, vincristine and alpha-interferon. The pathogenesis, varied clinical, laboratory, and histopathological features, and the management of IHES are reviewed.