Pigeon Exposure Triggers Acute Hypersensitivity Pneumonitis

A 27-year-old woman with no prior medical history developed acute hypoxic respiratory failure requiring up to 10 L/min of supplemental oxygen due to bird fancier’s lung, a form of hypersensitivity pneumonitis triggered by prolonged indoor exposure to a rescued pigeon housed in her family kitchen.

Domestic Pigeon Exposure Triggers Severe Hypoxic Respiratory Failure

She was a former smoker who had quit four years prior and reported no relevant occupational hazards. A detailed environmental evaluation revealed the source of her illness: an indoor rescued pigeon kept inside the household kitchen. Upon admission, her oxygen requirement climbed to 10 L/min, and an arterial blood gas test taken at that flow rate showed a partial pressure of oxygen (PaO₂) of 10.2 kPa with an oxyhaemoglobin saturation of 93.8%.

Computed tomography pulmonary angiography ruled out pulmonary embolism while revealing diffuse bilateral ground-glass opacities that concentrated in the upper lobes and perihilar regions. Blood tests recorded an elevated lactate dehydrogenase level of 423 U/L alongside a C-reactive protein reading of 43 mg/L. Routine panels for renal and liver function, complete blood counts, and cardiac biomarkers fell within normal parameters. Autoimmune screenings yielded negative results, though an isolated anticardiolipin IgG level measured 22 U against a 0–20 U reference range. Treating clinicians discounted this minor elevation given the absence of supporting clinical symptoms.

Serological Assays Show Elevated Antibodies Against Avian Antigens

Comprehensive panels for respiratory viruses and atypical pathogens returned negative findings. Serological assays identified markedly elevated immunoglobulin G (IgG) antibodies directed against pigeon serum, feathers, and droppings, registering above 200 mg/L against a normal ceiling of 40 mg/L. Similar elevations appeared for budgerigar antigens, while parrot-specific IgG reached 185 mg/L.

Comprehensive panels for respiratory viruses and atypical pathogens returned negative findings. Serological assays identified markedly elevated immunoglobulin G (IgG) antibodies directed against pigeon serum, feathers, and droppings, registering above 200 mg/L against a normal ceiling of 40 mg/L. Similar elevations appeared for budgerigar antigens, while parrot-specific IgG reached 185 mg/L.

Corticosteroids and Antigen Avoidance Improve Patient Breathing

Hospital management relied on strict avoidance of avian proteins coupled with systemic corticosteroid intervention. Physicians initiated oral prednisolone at 40 mg once daily, maintaining that dosage for two weeks before stepping it down to 30 mg daily for another fortnight, and subsequently to 20 mg daily. Supplemental oxygen was successfully removed three days after treatment began, and she left the hospital on day five breathing unassisted room air.

A follow-up assessment at three months led to a tapering schedule that eventually stopped the medication entirely. Subsequent computed tomography scans verified complete radiological clearance without residual pulmonary fibrosis. Contemporary diagnostic frameworks classify the condition as nonfibrotic hypersensitivity pneumonitis, reinforcing that early removal of the inciting trigger remains critical to halting disease progression.