[A case of chronic hypersensitivity pneumonitis due to wild pigeons]

A 61-year-old woman was admitted to the Oita Medical University Hospital because of a nonproductive cough and exertional dyspnea. Interstitial changes had been seen on her chest radiograph 5 years previously, but no respiratory symptoms were identified at that time. On admission, chest radiography revealed linear and ground-glass opacities in the middle and lower lung fields. Computed tomography provided evidence of bronchiectasis and micro-honeycombing of the lungs, while lymphocyte and neutrophil counts in the bronchoalveolar lavage fluid were increased. Transbronchial lung biopsy demonstrated alveolitis and Masson's bodies. The patient was not a pigeon breeder, but she could have been exposed to pigeons at her workplace. Indeed, she had specific antibodies against pigeon serum and droppings, and her peripheral lymphocytes showed proliferation in response to pigeon serum. A positive provocation test involving inhalation of pigeon serum confirmed that she had chronic hypersensitivity pneumonitis caused by allergy to pigeons. This is a rare case of chronic hypersensitivity pneumonitis associated with wild pigeons, that progressed to pulmonary fibrosis. Antigen provocation testing proved to be of great value.