Successful treatment of steroid resistant hypereosinophilic syndrome with low-dose CsA
A 41-year-old man who had been suffering from intractable eosinophilic pustular folliculitis for 5 years was referred to our hospital. Skin biopsy from the lesion showed perivascular and periadnexal eosinophilic infiltration. He had no history of allergies. Although he had been taking dapsone, prednisone, and an antihistamine since 2008, his skin lesion had waxed and waned and the CBC showed persistent hypereosinophilia for over 1 year. The laboratory results showed an eosinophil count of 1,790/mm3 and a serum IgE level of 119 IU/mL. Nevertheless, there was no evidence of secondary HES. Sequentially performed bone-marrow aspiration and biopsy showed hyperplasia of the eosinophilic lineage, but the molecular analysis did not show any specific aberrant genetic mutations consistent with the myelocytic variant of HES (M-HES). Unfortunately, we did not analyze the T cell phenotype and T cell clonality. On physical examination, only skin manifestations were found. The patient could not be categorized as L-HES according to the laboratory results; however, considering the relatively gentle clinical course and absence of cardiac involvement, we selected an immune-modulating drug as a second line treatment rather than a cytotoxic agent or imatinib. We administered a low dose of CsA (100 mg bid), and his eosinophil count returned to normal after 1 week of treatment. In addition, his skin lesion disappeared ().