Hypersensitivity Pneumonitis

Hypersensitivity pneumonitis (HP) is an immune-mediated inflammatory lung disease caused by inhaling specific organic dusts or chemicals. Common triggers include mold, bird droppings (bird fancier's lung), and farm exposures.

Table of Contents

Quick Facts

  • ICD-10: J67
  • Treatment: Avoid exposure, sometimes steroids

Symptoms

Acute form

  • Flu-like illness 4–6 hours after exposure
  • Fever, chills, body aches
  • Cough, shortness of breath

Chronic form

  • Progressive shortness of breath
  • Persistent cough
  • Weight loss, fatigue
  • Lung fibrosis on imaging

Common Triggers

  • Mold in damp environments
  • Bird droppings or feathers (parakeets, pigeons)
  • Hay or moldy grain (farmer's lung)
  • Hot tubs and humidifiers (bacteria)
  • Certain chemicals

Treatment

  • Identify and avoid the trigger (most important step)
  • Corticosteroids for moderate-severe disease
  • Oxygen if hypoxemic
  • Pulmonary rehabilitation
  • Antifibrotic medications for advanced chronic disease
Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about a medical condition. If you are experiencing a medical emergency, call your local emergency number immediately.

References

  • American Thoracic Society. Hypersensitivity Pneumonitis Guidelines.