[Pneumonitis induced by the herbal medicine Sho-saiko-to in Japan].

We studied the clinical characteristics of pneumonitis induced by Sho-saiko-to (SST). Of 94 cases reported to a drug maker, 72 were judged to be SST-induced pneumonitis (52 men and 20 women, mean age 63.7 years). Most patients took SST for chronic liver diseases due to infection with the hepatitis C virus. The mean duration of SST therapy before the onset of pneumonitis was 50.2 +/- 42.1 days. Most patients presented with coughing, dyspnea, and fever of acute onset. Chest X-ray films showed diffuse ground-glass shadows and infiltration. Abnormally high levels of C-reactive protein and lactate dehydrogenase were common, as was hypoxia. Analysis of bronchoalveolar lavage fluid revealed abnormally high percentages of lymphocytes and neutrophils and a low CD4/CD8 ratio. Although 64 of 72 patients survived after cessation of SST only or steroid therapy, 8 died of respiratory failure despite high-dose steroid therapy. Compared with patients who survived those who died were more likely to have an underlying lung disease, had been taking SST longer after the onset of pneumonitis, and had more severe hypoxemia.