Abnormal Cutaneous Response to Mosquito Bites in Cancer Patients

Abstract

A skin eruption simulating 'papular urticaria' was observed in 6% of 500 patients with cancer. Twenty seven of them had carcinoma affecting different organs, while 3 had lymphoma. Direct observation revealed that the skin lesions were the result of bites by the mosqmtoes. There was direct correlation between mosquito bite reaction and the response to iadermal tests with mosquito antigen , (MSA). The leucocytee migration inhibition test usmg MSA revealed the existence of cell mediated immunity to MSA in these patients with 'papular urticaria'. Specific treatment for malignancy apparently influenced the pattern of reaction to ID test as well as to mosquito bites. The histopathologic studies revealed non-- specific changes in the delayed papules after mosquito bites. The MAS test papules closely simulated morphologically and histologically, te delayed papules of mospuito bites. None of the 12 attendants of cancer patients who were exposed to similar environment as that of cancer patient, while in the ward or at home, developed similar reaction either to MSA or to direct mosquito bite. None of the healthy volunteers or patients with diseases other than cancer, developed similar reaction either to MSA or to direct bites by mosquities. The role of irradiation and malignancy in the abolition of 'Suppressor T cell" activity in the aetiology of these skin eruptions is discussed.