Ethambutol-induced pulmonary infiltrates with eosinophilia and skin involvement

A 67 year old woman presented with miliary tuberculosis. She was treated with streptomycin, isoniazid, rifampicin, ethambutol and pyrazinamide. However, she developed rifampicin-induced thrombocytopenia after 6 weeks of treatment, and skin rash, blood eosinophilia and pulmonary infiltrates after 8 weeks of therapy. The latter was found to be ethambutol related. Additional evidence, including blood and sputum eosinophilia and the rapidity of its response to corticosteroid, suggested that the pulmonary infiltrates might also be eosinophilic in nature. To the best of our knowledge, this constitutes the first report of such adverse drug reaction, induced by ethambutol.