The idiopathic hypereosinophilic syndrome.

: Idiopathic hypereosinophilic syndrome (HES) is empirically defined as the presence of prolonged eosinophilia without an identifiable underlying cause, and with evidence of end-organ dysfunction. Virtually any organ system may be involved, most frequently the heart, the central and peripheral nervous system, the lungs and the skin. We report on two clinical cases where the diagnosis of HES, with all the conventional criteria met, was proposed. In the first patient with HES, cardiac and pulmonary involvement was present. Skin changes and lung involvement were observed in the second reported patient with HES. In both patients there was prompt improvement of all clinical signs and symptoms of HES soon after treatment with methylprednisolone was begun. In the first patient long-term methylprednisolone therapy was healed successfully. For 2 years he has shown no clinical signs or symptoms of HES. The second patient is still undergoing long-term therapy with 4 mg of methylprednisolone daily. The histologic findings of the skin biopsy in the second patient were not typical for HES, but skin changes completely healed after corticosteroid therapy. This could mean that that the described skin changes were one of the HES skin manifestations. The other possibility is that the skin changes emerge in coincidence with HES.