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hypersensitivity pneumonitis

Thursday 17 May 2007

Definition: Hypersensitivity pneumonitis (extrinsic allergic alveolitis) caused by inhaled allergens can progress to disabling or even fatal end-stage lung disease. The only truly effective treatment is early recognition and control of exposure.


- Hypersensitivity pneumonitis


- CD8(+) cytotoxic lymphocytes infiltration
- multinucleate giant cell granulomas
- pulmonary interstitial fibrosis
- small airways disease with obstruction


- occupational dusts or mists
- residential exposure

  • pet birds (pigeons and parakeets)
  • contaminated humidifiers
  • indoor molds

- serum IgG containing high titers of specific antibody to the offending antigen elevated
- pulmonary function tests: restrictive and diffusion defects with hypoxemia, especially after exercise


- Patel AM, Ryu JH, Reed CE. Hypersensitivity pneumonitis: current concepts and future questions. J Allergy Clin Immunol. 2001 Nov;108(5):661-70. PMID: 11692086