Tropical eosinophilia: clinical and physiological response to diethylcarbamazine.

Fifty patients with tropical eosinophilia were studied clinically and physiologically, before and after a standard 3-week course of diethylcarbamazine. Before treatment the main physiological abnormality was a reduction in the carbon monoxide transfer factor. One month after the start of treatment most patients had shown a marked symptomatic improvement, but peripheral blood eosinophilia persisted in 52%, radiographic abnormalities in 44%, cough in 22% and chest signs in 8%. Significant improvement was noted in almost all aspects of lung function including blood gases, but the mean values for forced expiratory volume in one second, forced vital capacity, transfer factor and transfer coefficient continued to be significantly lower than predicted values. This study demonstrates the incomplete reversal of clinical, haematological, radiological and physiological changes in tropical eosinophilia one month after starting a 3-week course of diethylcarbamazine.