Hypersensitivity pneumonitis secondary to lovebirds: a new cause of bird fancier's disease.

Hypersensitivity pneumonitis (HP) is an immunologically mediated lung disease due to the repetitive inhalation of antigens. Most new cases arise from residential exposures, notably to birds, and are thus more difficult to recognise. The present authors report a 59-yr-old male who complained of dyspnoea and cough while being treated with amiodarone. Pulmonary function tests revealed restriction and obstruction with low diffusing lung capacity for carbon monoxide and partial pressure of oxygen. A high-resolution computed tomography chest scan and bronchoalveolar lavage showed diffuse bilateral ground-glass attenuation and lymphocytic alveolitis, respectively. Initial diagnosis was amiodarone pulmonary toxicity, but because of a rapidly favourable evolution, this diagnosis was questioned. A careful environmental history revealed a close contact with lovebirds shortly before the onset of symptoms. Precipitins were strongly positive against lovebird droppings, but were negative against other avian antigens. The patient was diagnosed with hypersensitivity pneumonitis to lovebirds. Avoidance of lovebirds and steroid treatment led to rapid improvement. The present observation identifies a new causative agent for hypersensitivity pneumonitis and highlights the importance of a thorough environmental history and of searching for precipitins against antigens directly extracted from the patient's environment. These two procedures should allow a more precise classification of some cases of pneumonitis, and thus might avoid progression of active undiagnosed hypersensitivity pneumonitis to irreversible fibrosis or emphysema.