Bird-related non-fibrotic hypersensitivity pneumonitis with bronchoalveolar lavage fluid eosinophilia that developed after COVID-19 vaccination: A case report.

A 60-year-old man who had been keeping seven budgerigars and four cockatiels in his house for 2 years developed dyspnea and was admitted to our hospital the day after receiving the second dose of the messenger RNA coronavirus disease 2019 vaccination. Chest high resolution computed tomography (HRCT) showed bilateral ground glass opacities without nodules or mosaic attenuation. IgG specific for budgerigars was positive. Although his respiratory symptoms were resolved without corticosteroid therapy, he developed severe dyspnea soon after the discharge to his home. The results of bronchial alveolar lavage fluid obtained at the initial admission and after the provocation challenge showed elevation of lymphocytes (34%) and eosinophils (37%). We finally diagnosed him with non-fibrotic bird-related hypersensitivity pneumonitis. His condition and HRCT findings were improved by corticosteroid treatment. All his birds were given away. He has not experienced any recurrence or deterioration of respiratory function even after withdrawal of corticosteroid.