Hypersensitivity pneumonitis (HP), or extrinsic allergic alveolitis, refers to a clinical syndrome and pattern of lung inflammation occuring in response to a wide variety of inhaled antigens. The prototypical form, “bird-fancier’s lung”, has been ascribed to several avianexposures, predominantly pigeons and budgies. We report a case of HP associated with pheasant exposure and confirmed by pheasant-specific allergen testing.
A 28-year-old pheasant farmer with a past medical history significant for seasonal allergies and “asthma” presented to his primary doctor with acute onset of fatigue, dyspnea, productive cough and fever. Chest radiographs revealed a right upper lobe infiltrate (Fig 1). He was diagnosed with pneumonia and prescribed consecutive courses of azithromycin, doxycycline and augmentin over a 2 week period. In spite of interval clearing of the radiograph (Fig 2) and normal office spirometry, there was no clinical improvement. The patient had worked on a pheasant farm for 9 years, caring for and cleaning the pheasants and their cages, with frequent, often heavy, dust exposure. At this point hypersensitivity pneumonitis was suspected, and he was advised to avoid this workplace. Testing for psittacosis, histoplasmosis and cryptococcosis was negative. Pulmonary function testing then demonstrated a restrictive pattern with a vital capacity of 63% of predicted and diffusing capacity of 60% of predicted; a high resolution CT of the chest was negative. 3 months after his initial presentation and one month after ceasing pheasant exposure, he was referred to our clinic. We evaluated the suspicion of pheasant-related HP formally via skin testing to pheasant coop dust, which was positive. His fever had resolved but dyspnea, fatigue and cough continued. With prolonged avoidance of pheasants over the following year, his symptoms gradually resolved and pulmonary function test results became normal.
“Pheasant hypersensitivity” was previously reported by Peters and coworkers in a pheasant hobbyist, but this individual was also chronically exposed to ducks, an exposure known to be associated with HP. Furthermore, in their report, pheasant dropping extract produced negative scratch testing and non-specific skin prick results (control subjects also developed a wheal and flare). Most importantly, the diagnosis of HP in their case report was difficult to distinguish from asthma, since the symptoms included fatigue and wheezing but not fever, because the limited pulmonary function data did not show evidence for restriction, and because there was no infiltrate on chest radiographs. In comparison, our patient demonstrated high fevers, a transient radiographic infiltrate, and restrictive pulmonary function testing that improved after cessation of antigen exposure. Pheasants are farmed for use both in hunting releases and as food; by many they are considered a delicacy. Estimates on the precise number of persons working directly with pheasants are difficult to obtain, but their numbers may be increasing due to the increasing popularity of pheasants.
The list of specific exposures associated with hypersensitivity pneumonitis continues to grow. By quickly recognizing the potential for a novel association with pheasant exposure, this worker was quickly removed from an injurious environment. Our confidence in the diagnosis of HP was strengthened by specific cutaneous hypersensitivity to local pheasant coop dust. The patient’s fevers, a transient radiographic infiltrate and restrictive pulmonary function test results helped to differentiate his condition from asthma. This well-documented case convincingly reports HP associated with pheasant exposure, without a confounding exposure known to be associated with HP.
C.R. Carlsten, None.