Pigeon breeder's lung is a form of hypersensitivity pneumonitis, which is caused by repetitive exposure to pigeon antigen. The clinical manifestations are classified according to the phase, which is acute, subacute, or chronic. The diagnosis is based on the clinical picture, environmental and patient history, physical exam, and the appropriate studies.
Pigeon breeder's lung (PBL) is an extrinsic allergic alveolitis secondary to inhalation of pigeon antigen . Specifically, this ailment stems from persistent exposure to droppings as well as feather and serum proteins of pigeons and other birds. Hypersensitivity pneumonia is frequently caused by avian antigens , which emerge from both domestic exposure  and the global poultry handling industry.
The clinical presentation of symptomatic hypersensitivity pneumonitis is characterized as acute, subacute, or chronic, which is associated with symptoms of differing intensity and timing  . Acute cases develop hours post exposure and resolve hours to days after withdrawal of exposure. Patients will experience fever, cough, headache, dyspnea, malaise, and chills. The subacute disease is characterized by an insidious onset that may take weeks to months, in which there is a progressive cough, shortness of breath and possibly anorexia. Chronic manifestations of this condition include fatigue, persistent cough, worsening dyspnea, anorexia, and weight loss . Patients with pigeon breeder's lung do not respond to anti-asthma therapy.
One potential long-term sequela of this disease is the progression to irreversible fibrosis or other structural abnormalities  .
Vital signs in acute episodes are notable for fever, tachycardia, tachypnea, and oxygen desaturation . The lung exam may be remarkable for use of accessory muscles. Findings on auscultation may include bibasilar crackles.
Entire Body System
Additional symptoms may include chills, sweating, aching, and fatigue. Most cases involve typical episodes that are mild and short and may be misdiagnosed. [healthcentral.com]
The subacute form is characterized by the insidious onset of productive cough, dyspnea, and fatigue over weeks to months. Chronic hypersensitivity pneumonitis is characterized by long-term progressive dyspnea, weight loss, cough, and fatigue. [amboss.com]
The chronic form of hypersensitivity pneumonia results from long term low-grade exposure, and is characterized by dyspnea, chronic cough, fatigue, anorexia and weight loss. PFT typically reveals a restrictive pattern and a decrease in DLCO. [indianpediatrics.net]
Chronic manifestations of this condition include fatigue, persistent cough, worsening dyspnea, anorexia, and weight loss. Patients with pigeon breeder's lung do not respond to anti-asthma therapy. [symptoma.com]
In the chronic form there is usually anorexia, weight loss, extreme fatigue and progressive pulmonary fibrosis, which is generally the most serious consequence of the disease because it irreversibly and increasingly diminishes the lungs' efficiency over [en.wikipedia.org]
- Exposure to Pigeon Droppings
Researchers suggest that just as long-term exposure to cockroaches and mice can lead to allergic conditions in senstive individuals, so also can long term exposure to pigeon droppings. [wildlifecontrolconsultant.com]
In addition to evaluation of the clinical picture, diagnosis of pigeon breeder's lung is achieved by assessing the patient's environmental exposures , detailed history, physical exam, and the appropriate studies. It is also important to rule out differential diagnoses such as tuberculosis, sarcoidosis, connective tissue diseases, mycoplasma, allergic bronchopulmonary aspergillosis, Langerhans cell histiocytosis, malignancies and others   .
Some authors argue that a diagnosis is achieved by demonstration of specific antibodies, a positive skin prick test, and cessation of symptoms following the withdrawal of exposure  .
High-resolution CT (HRCT) scanning in acutely ill patients displays ground-glass opacities that are particularly observed in the lower lobes . In the chronic phase, HRCT displays fibrotic changes, centrilobular nodular lesions, honeycombing, traction bronchiectasis, ground glass attenuation, and irregular linear opacities   .
Pulmonary function tests are important components of the workup. Acute cases will demonstrate a restrictive pattern in which the total lung capacity and forced vital capacity are diminished. Chronic disease is associated with either a restrictive or a mixed picture with both obstructive and restrictive pattern.
Additionally, the diffusing capacity of lungs for carbon monoxide (DLCO) is decreased . The inhalation challenge is another test in which the patient is exposed to the offending agent for confirmation.
Cytology on specimens from bronchoalveolar lavage (BAL) may be inconclusive  but will typically display lymphocytosis . A lung biopsy is not necessary, but findings such as foamy histiocytes from interstitial and alveolar samples are consistent with hypersensitivity pneumonia  .
- Rodrigo M, Benavent M, Cruz M, et al. Detection of specific antibodies to pigeon serum and bloom antigens by enzyme linked immunosorbent assay in pigeon breeder’s disease. Occup Environ Med. 2000;57(3):159-164.
- Kurup VP, Zacharisen MC, Fink JN. Hypersensitivity pneumonitis. Indian J Chest Dis Allied Sci. 2006;48(2):115-128.
- Funke M, Fellrath JM. Hypersensitivity pneumonitis secondary to lovebirds: a new cause of bird fancier's disease. Eur Respir J. 2008;32(2):517-521.
- Lacasse Y, Girard M, Cormier Y. Recent advances in hypersensitivity pneumonitis. Chest. 2012;142(1):208-217.
- Fink JN, Sosman AJ, Barboriak JJ, Schlueter DP, Holmes RA. Pigeon breeders' disease. A clinical study of a hypersensitivity pneumonitis. Ann Intern Med. 1968;68(6):1205-1219.
- Tsanglao WR, Nandan D, Chandelia S, Bhardwaj M. Chronic Hypersensitivity Pneumonia due to Pigeon Breeders Disease. Indian Pediatr. 2017;54(1):55-57.
- Morell F, Roger A, Reyes L, Cruz MJ, Murio C, Muñoz X. Bird fancier's lung: a series of 86 patients. Medicine (Baltimore). 2008;87(2):110–130.
- Fan LL, Deterding RR, Langston C. Pediatric interstitial lung disease revisited. Pediatr Pulmonol. 2004;38(5):369-78.
- Deutsch GH, Young LR, Deterding RR, Fan LL, Dell SD, Bean JA, et al. Diffuse lung disease in young children:
application of a novel classification scheme. Am J Respir Crit Care Med. 2007;176(11):1120-1128.
- Morell F, Curull V, Orriols R, et al. Skin test in bird breeder’s disease. Thorax. 1986;41(7):538–41.
- Richerson HB, Bernstein IL, Fink JN, et al. Guidelines for the clinical evaluation of hypersensitivity pneumonitis. Report of the Subcommittee on Hypersensitivity Pneumonitis. J Allergy Clin Immunol.1989;84(5 Pt 2):839–844.
- Lynch DA, Rose CS, Way D, King TE Jr. Hypersensitivity pneumonitis: sensitivity of high-resolution CT in a population-based study. Am J Roentgenol. 1992;159(3):469-472.
- Ratjen F, Costabel U, Griese M, Paul K. Bronchoalveolar lavage fluid findings in children with hypersensitivity pneumonitis. Eur Respir J. 2003;21(1):144-148.
- Riley DJ, Saldana M. Pigeon breeder’s lung. Subacute course and the importance of indirect exposure. Am Rev Respir Dis. 1973;107(3):456-460.