Tropical eosinophilia in a man from Sri Lanka

A 21-year-old man from Sri Lanka came to Japan in August 1992 and worked as a painter. He had often complained of dyspnea on exertion before coming to Japan. He was admitted to Ogaki Municipal Hospital in June 1993 for further examination of persistent coughing, dyspnea, and fever. A chest X-ray film showed bilateral diffuse reticulonodular shadows. Blood examinations revealed marked eosinophilia (9440/mm3) with elevation of the serum IgE level (4982 IU/ml). IgG enzyme-linked immunosorbent assay showed a high titer against Dirofilaria immitis. Microfilaria were not detected in blood sampled at night. He was given a diagnosis of tropical eosinophilia. We could not give diethyl-carbamazine. Filariasis is seldom encountered in Japan, but we emphasize that parasitic disease such as tropical eosinophilia must be considered in the differential diagnosis if the patient is from a tropical area where filariasis is common.