Hypersensitivity Pneumonitis mini-review

Clinical Presentation

Although symptoms occasionally develop after just a few weeks of contact with the allergen, most cases of hypersensitivity pneumonitis occur following months or years of continuous or intermittent inhalation of the inciting agent.

  • Acute: fever, chills, myalgia, headache, coughing, chest tightness, dyspnea, and leukocytosis
  • Chronic: gradual onset of exertional dyspnea, fatigue, coughing, sputum production, anorexia, and weight loss. Bibasilar crackles are typically audible and finger clubbing may be present



  • CXR: reticular pattern, honeycombing; sometimes are more severe in the upper lobes
  • CT: ground-glass opacity, air trapping, and centrilobular nodules, traction bronchiectasis
  • BAL: lymphocytic lavage


  • Remove the offending agent.
  • 40–60 mg of prednisone daily and taper