Paediatric feather duvet hypersensitivity pneumonitis

A previously well 12-year-old boy was admitted with a second insidious episode of dyspnoea, dry cough, anorexia, weight loss and chest pain. At admission, he had an oxygen requirement, significantly impaired lung function and reduced exercise tolerance. Initial forced expiratory volume in 1 s was 26%; a 3 min exercise test stopped at 1 min 50 when saturations dropped to 85%. CT scan showed ground-glass nodularity with lymphadenopathy. Bronchoalveolar lavage (BAL) for Pneumocystis carinii pneumonia and viruses were negative, and microbiology results for the BAL were reported in the absence of histology. This is because at the time the BAL samples were collected, a lung biopsy was performed. The biopsy was consistent with hypersensitivity pneumonitis. Echo was normal and CT pulmonary angiography negative. After taking a thorough history, exposure to feather duvets prior to each episode was elicited. IgG of avian precipitants was raised at 10.6 mgA/L (normal <10 mgA/L). Clinical improvement began with avoidance of exposure, while the boy was an inpatient. Antigen avoidance continued on discharge. He continues to improve since discharge. The condition was diagnosed as hypersensitivity pneumonitis secondary to exposure to antigens from feather duvets.