Hypersensitivity pneumonitis secondary to residential exposure to Aureobasidium pullulans in 2 siblings

Background: Hypersensitivity pneumonitis (HP) is an immune-mediated hypersensitivity reaction to a variety of inhaled particles that may lead to acute, subacute, or chronic interstitial pneumonitis and possibly end-stage lung disease. Avian antigens most commonly cause HP in children, but fungi have also been implicated. Objective: To describe a 15-year-old girl and her 6-year-old brother who developed HP from residential exposure to Aureobasidium pullulans. Methods: Allergy skin testing, serum precipitating antibodies, pulmonary function testing, chest radiography, chest computed tomography. bronchoalveolar lavage. and a home survey for possible causative antigens were performed. Results: Both patients lived on a horse farm and had fatigue, weight loss, cough, and dyspnea. The siblings had restrictive patterns on pulmonary function tests, with decreased diffusion capacity of carbon monoxide, ground-glass opacities on high-resolution chest computed tomography, and serum precipitins to A pullulans. Bronchoalveolar lavage in the girl demonstrated lymphocytosis, with a preponderance of CD8(+) T cells and natural killer cells. Symptoms improved after the children vacated the home and recurred on repeated exposure in both patients. Home evaluation revealed extensive mold contamination, with A pullulans counts of 659, 329, and 71 CFU/m(3) in the boy's bedroom, the girl's bedroom, and outdoors, respectively. Conclusions: The diagnosis of HP in these siblings is supported by the clinical history, the diagnostic findings, and the recurrence of symptoms on repeated exposure. These cases represent the second report of HP resulting from nonoccupational exposure to A pullulans in North America and the first report in children.