Evaluation of clinical and radiological features of patients diagnosed with hypersensitivity pneumonia

Background Hypersensitivity pneumonitis (HP) is an inflammatory fibrotic disease that affects the lung parenchyma and small airways. Aims Our study aimed to evaluate the clinical and radiological features of patients with an HP diagnosis in follow-up. Study Design: A retrospective cross-sectional study. Methods Our study included 100 patients diagnosed with HP who were diagnosed and managed in our clinic between 2020 and 2024. Clinical data, comorbidities, pulmonary function test-carbon monoxide diffusion capacity (PFT-DLCO) parameters, six-minute walk test results, high-resolution lung computed tomography (HRCT) patterns, prognosis, and mortality data were retrospectively documented. Results In our study, the male–female ratio was equal (50–50). The mean age was 63 (± 14). The majority of the patients were active smokers. While 65% of the patients were exposed to an organic or inorganic agent, 86.4% of all known exposures were caused by exposure to birds and bird products. A total of 29 patients (29%) were diagnosed by surgical sampling. The most common HRCT findings were reticulation (87%), ground-glass opacities (84.7%), and centrilobular nodules (75%). Fibrosis findings were seen in 40% of the patients. Glucocorticoids were the main treatment (77%), and 20 (20%) patients also required antifibrotic treatment. When correlation analyses were performed, the neutrophil count showed a negative correlation with the presence of a mosaic pattern, while a positive correlation was found with the presence of honeycombing. The basophil count had a positive correlation with exposure to birds and bird products. Conclusion There are no guidelines or consensus published in Turkiye regarding the diagnosis and treatment of HP. In our study, the positive correlation between the neutrophil count of the patients and the development of fibrosis in HRCT suggested that neutrophilia may also be a poor prognostic factor. The positive correlation between exposure to birds and bird products and basophilia was a striking finding.