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Familial summer-type hypersensitivity pneumonitis in Japan: two case reports and review of the literature

Akira Nakajima1, Takeshi Saraya1*, Takeshi Mori2, Reiko Ikeda3, Takashi Sugita3, Takayasu Watanabe1, Masachika Fujiwara4, Hajime Takizawa1 and Hajime Goto1

Author Affiliations

1 Department of Respiratory Medicine, Kyorin University School of Medicine, 6-20-2 Shinkawa, 181-8611, Mitaka City, Tokyo, Japan

2 Division of Hematology, Department of Internal Medicine, Juntendo University School of Medicine, 2-1-1 Hongou, 113-8421, Bunkyo ward, Tokyo, Japan

3 Department of Microbiology, Meiji Pharmaceutical Universitys,2-522-1 Noshio, 204-0004, Kiyose city, Tokyo, Japan

4 Department of Pathology, Kyorin University School of Medicine, 6-20-2 Shinkawa, 181-8611, Mitaka City, Tokyo, Japan

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BMC Research Notes 2013, 6:371  doi:10.1186/1756-0500-6-371

Published: 13 September 2013



Hypersensitivity pneumonitis is defined as an allergic lung disease that occurs in response to inhalation of fungal antigens, bacterial antigens, chemicals, dusts, or animal proteins. The incidence of summer-type hypersensitivity pneumonitis is higher in the summer season, especially in Japan, due to the influence of the hot and humid environment and the common style of wood house or old concrete condominiums.

Case presentation

The present report describes a case of a middle-aged married couple who lived in the same house and who simultaneously suffered from summer-type hypersensitivity pneumonitis. This report analyzes these two cases in terms of environmental research and its microbiological, radiological, and pathological aspects. This case report is followed by a review of family occurrences of summer-type hypersensitivity pneumonitis from 22 studies with a total of 49 patients (including the two present cases) in Japan.


Summer-type hypersensitivity pneumonitis may be unrecognized and misdiagnosed as pneumonia or other respiratory diseases. A greater understanding of the clinical, pathologic, and environmental features of summer-type hypersensitivity pneumonitis might help improve diagnosis and delivery of appropriate management for this condition.

Familial summer-type hypersensitivity pneumonitis; Climate; Geography; Trichosporon species; Environmental factor