Abstract
Mosquito bites are classified into 4 clinical types of urticaria type, prurigo type, hypersensitivity type and fatal type. Urticaria and prurigo type are very common, but hypersensitivity and fatal type are moderately rare. Twenty-seven patients with mosquito hypersensitivity have been reported in Japan. Fatal cases were 11 out of 27 patients. The cause of death was malignant histiocytosis in 9 patients, intracranial hemorrhage and unknown malignancy in each one. In this presentation, 2 patients with mild type of mosquito bites and 3 patients with mosquito hypersensitivity were reported. The histologic appearance of the skin lesions of mosquito hypersensitivity corresponded to Arthus type vasculitis. A 18-year-old woman with mosquito hypersensitivity died of renal insufficiency, and histologic examinations after autopsy revealed the infiltration of histiocytic tumor cells in the liver, spleen and kidney. A 23-year-old woman with past episodes of mosquito hypersensitivity had ulcerated lesion on the right leg, histologically diagnosed as malignant histiocytosis. She died after 7 months in spite of various treatments.
