[Development of eosinophilic pneumonia in a patient with latent tuberculosis infection resulting from isoniazid].

We report a 37-year-old patient with latent tuberculosis infection who received isoniazid (INH) antituberculosis chemoprophylaxis. However, he developed fever and productive cough 3 weeks after treatment. Chest radiography and computed tomography showed bilateral infiltrative shadows in upper fields. Bronchoalveolar lavage fluid revealed a high proportion of eosinophils, and histological examination of biopsied lung tissue showed interstitial thickening with eosinocyte infiltration. Based on these findings, the patient was diagnosed with drug-induced eosinophilic pneumonia. His febrile condition and dry cough resolved after discontinuation of INH. Chest X-rays showed improvement of infiltrative shadows. This case report highlights the potential for INH-induced pneumonitis during the course of antituberculosis chemoprophylaxis.