Hypersensitivity pneumonitis is subdivided into two forms: acute and chronic. Symptoms differ for each form.
The acute form of HP occurs after heavy, often short-term exposure to the antigen. Symptoms appear relatively suddenly and include:
If the person is removed from the antigen exposure, the symptoms usually resolve over 24 to 48 hours. Recovery is often complete.
The chronic form of HP is thought to occur due to longer term, low-level exposure to the antigen, and it often causes more subtle symptoms. Patients with chronic HP often describe chronic symptoms, such as shortness of breath or cough, that have gotten worse. Symptoms may worsen at work, at home or wherever the patient is being exposed to the antigen, but most often, patients with chronic HP haven't had acute episodes. Most patients seen in our clinic have the chronic form of HP.
Reviewed by health care specialists at UCSF Medical Center.