Symptoms Make an Appointment Refer a Patient Ask a Question Reviewed by Cecile S. Rose, (June 01, 2012) Symptoms of brief or severe (acute) hypersensitivity pneumonitis often occur 6-8 hours after exposure to the foreign substance. Symptoms may include: chills, fever, cough, and shortness of breath. Symptoms of long-lasting (chronic) HP include: gradual onset of shortness of breath (especially with activity), cough, unusual fatigue, loss of appetite, and unintentional weight loss. Causes Diagnosis Clinical Trials For more than 100 years, National Jewish Health has been committed to finding new treatments and cures for diseases. Search our clinical trials.