Farmer's lung disease is a type of allergic pneumonia specifically associated with breathing air in areas of hay, grain or silage that are contaminated with various molds or heat-tolerant bacteria. Homes and offices with poor air handling maintenance may also be sources of farmer's lung disease. A variety of symptoms may occur following exposure to these conditions which include coughing, shortness of breath and flu-like symptoms with chills, fever, and headache.

Diagnosis of farmer's lung may include a patient history of this kind of exposure producing symptoms and a blood test. The blood test may show antibodies to the molds or bacteria causing the symptoms.

Treatment of farmer's lung disease may be as simple as avoidance of exposure to the contaminated source. This can mean wearing a respirator or face mask, or removing the source of the molds and bacteria. If an air conditioner or humidifier is involved, thorough cleaning with soap and water or Clorox solution may suffice. Symptoms of disease often disappear when the source of the problem is eliminated.