Abstract
A 64-year-old man was prescribed maoto, a prevailing Chinese herbal, for a cold with upper respiratory inflammation. Two days later, he developed a high fever, progressive dyspnea and pulmonary infiltration on chest high-resolution computed tomography (HRCT) including diffuse ground-glass opacity mainly around bronchovascular bundles and partial distribution of subpleural cysts resembling honeycombing. Despite the administration of azithromycin and pazufloxacin, the pulmonary infiltration and hypoxemia has rapidly progressed, so he was referred to our hospital. Although fulminant pneumonia or the acute exacerbation of idiopathic pulmonary fibrosis (IPF) was considered, his respiratory symptoms and pulmonary infiltration immediately improved and oxygen therapy was not needed on the fifth hospital day. Based on the clinical course, laboratory findings and the chest imaging findings, drug induced interstitial lung disease was suspected. The drug-induced lymphocyte test (DLST) as well as a scratch test against maoto demonstrated positive results. This is the first case report of maoto-induced interstitial pneumonia that was diagnosed based on the patient's clinical course, chest imaging findings and laboratory findings.