Tropical Pulmonary Eosinophilia: An Epidemiological and Clinical Review

Abstract

Pulmonary diseases associated with parasitic infections of the lung are unusual. However, the rise in immunosuppressive conditions such as HIV/AIDS, use of antineoplastic agents and post-transplant medications as well as the phenomenon of globalization and migration, has raised its prevalence both in immunocompromised and immunocompetent individuals. Tropical pulmonary eosinophilia (TPE) is a neglected tropical disease of predominantly filarial endemic countries caused by a hypersensitivity response to antigens from microfilariae of Wuchereria bancrofti and Brugia malayi. The disease affects less than 1% of patients with lymphatic filariasis, mainly young adult males. It has a slow onset of several months with respiratory symptoms mainly fever, cough, dyspnea and wheeze. The current criteria for the diagnosis of TPE include history supportive of exposure to lymphatic filariasis, nocturnal cough and dyspnea, pulmonary infiltrates in chest x-ray, elevated peripheral blood eosinophils and serum IgE levels, increased titers of anti-filarial antibodies and clinical response to diethylcarbamazine which is the standard treatment. When treated, the majority of patients recover clinically and functionally, however, a small group of patients develops features compatible with pulmonary interstitial fibrosis which encompasses a worse prognosis and ultimately a premature death. More research is necessary to understand the immunopathology of this disease and consequently improve our tools for early diagnosis and timely treatment.