Abstract
This case report presents a unique and severe manifestation of drug-induced interstitial lung disease (DIILD) in an 18-year-old male with a recent history of coronavirus disease 2019 (COVID-19) infection. The patient, treated with trimethoprim-sulfamethoxazole (Bactrim) for acne, developed a rapid and aggressively progressive respiratory failure and underwent bilateral orthotopic lung transplantation. Radiologic evaluation revealed extensive bilateral bronchiectasis, ground-glass opacities/consolidation, and fibrotic changes, with diffuse vascular thrombosis observed during explant pathology. Sulfonamides, particularly Bactrim, are implicated in DIILD, with male sex and pre-existing lung disease as common risk factors. The patient's simultaneous exposure to COVID-19 and genetic susceptibility to Bactrim allergy (human leukocyte antigen (HLA) B07:02 and HLA C07:02) may have contributed to the rapid progression of pulmonary fibrosis. Despite limited literature on lung transplantation for Bactrim-induced lung fibrosis, this case underscores its consideration as a viable treatment option in refractory cases.