DOI: https://doi.org/10.36347/sjmcr.2026.v14i07.025

Pages: 1718-1723

Background: Hypersensitivity pneumonitis is an immune-mediated interstitial lung disease caused by repeated inhalation of inciting antigens. Quaternary ammonium compounds are widely used in detergents and disinfectants and may cause respiratory toxicity through irritant, sensitizing, or adjuvant mechanisms. Their role in parenchymal lung disease remains insufficiently recognized. Case presentation: We report three women with hypersensitivity pneumonitis probably associated with repeated exposure to quaternary ammonium compound-containing detergent products, after exclusion of other identifiable inciting antigens. The first patient, a 63-year-old professional cleaner, developed a typical nonfibrotic pattern after two months of intense exposure. High-resolution computed tomography showed mosaic attenuation, expiratory air trapping, and centrilobular micronodules, and bronchoalveolar lavage fluid contained 30% lymphocytes. Strict exposure avoidance and oral corticosteroids were followed by favorable clinical, functional, and radiological outcomes. The second patient, a 60-year-old homemaker, developed typical fibrotic hypersensitivity pneumonitis after three years of exposure. She showed clinical and functional improvement after strict exposure avoidance, corticosteroids, and azathioprine, while residual fibrosis remained stable on computed tomography. The third patient, a 66-year-old professional cleaner with prolonged exposure, had typical fibrotic hypersensitivity pneumonitis. Despite repeated education and counseling regarding strict exposure avoidance, she continued to be exposed to the implicated detergent products. Her symptoms improved under corticosteroids and azathioprine, but lung function and imaging findings worsened; antifibrotic therapy was subsequently approved after multidisciplinary discussion. Conclusion: These cases illustrate a spectrum of detergent-associated hypersensitivity pneumonitis ranging from reversible nonfibrotic disease to progressive f