Drug-induced interstitial pneumonia results when exposure to drugs results in inflammation, which progresses to fibrosis of the lung interstit-ium. We report on a case of drug-induced interstitial pneumonia caused by Japanese herbal medicine (shini-seihai-to) that was difficult to differentiate from coronavirus disease 2019 (COVID-19) pneumonia due to similarities in clinical features and chest computed tomography (CT) findings. A 72-year-old woman visited a local clinic with complaints of fever and dif-ficulty with breathing and was referred to our hospital because of suspected pneumonia. Chest CT revealed ground-glass and reticular opacity in all lung fields bilaterally. Initially, we suspected COVID-19 pneumonia based on the CT findings and clinical features, but nasopharyngeal swab-based testing and PCR assay for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen were both negative. However, 45 days before ad-mission the patient had been treated for sinusitis with Japanese herbal medicine (shini-seihai-to). Thus, we suspected drug-induced interstitial pneumonia caused by this herbal preparation. Corticosteroid therapy for drug-induced interstitial pneumonia was initiated with prompt improvement. This case highlights the fact that drug-induced interstitial pneumonia, spe-cifically Japanese herbal medicine (shini-seihai-to)-induced interstitial pneumonia, may be considered in the differential diagnosis of COVID-19 pneumonia.

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A healthy 28-year-old woman presented to the emergency department with 2 days of malaise. On the day of presentation, she complained of dyspnea. The clinical findings (fever, shock, altered consciousness, and bilateral pulmonary shadows on chest imaging) were consistent with severe community-acquired pneumonia. Soon after presentation, she suffered from sudden cardiopulmonary arrest, and died two hours later. Later, cultures of sputum and blood grew Pseudomonas aeruginosa, and she was given a diagnosis of community-acquired pneumonia due to P. aeruginosa.

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