A couple in their seventies who lived together were the patients in this study. The wife began to experience shortness of breath, and then the husband also developed similar symptoms. Pathological examination findings, via a bronchoscopy of the husband, and computed tomography scans were consistent with summer-type hyper sensitivity pneumonitis. In addition, we confirmed that they also had serum antibodies against Trichosporon asahii. Accordingly, a diagnosis of summer-type hypersensitivity pneumonitis was made. They had severe dyspnea and fatigue, and so were treated with prednisolone. They were advised to change their residence as a treatment modality, although no evidence of T. asahii was obtained from the samples, which looked like some type of fungi, collected from the furniture and air purifier in their home. Neither had had any recurrence twelve months after the steroid therapy and changing their residence. This disease is thought to be scarce in winter, with such a familial case as in this study even rarer.
This case suggests that more people will develop summer-type hypersensitivity pneumonitis regardless of the season as our housing environments have changed.