A group of uncommon diseases of the lung are due to an immunologic response of the lung tissue to some environmental offenders. Unlike usual allergies that cause nasal congestion, watery itchy eyes, and cough, these exposures may cause changes in lung function and changes on x-rays and CT scans of the chest. Hypersensitivity lung disease may cause permanent lung damage. It is also easily overlooked since many other diseases can cause similar symptoms. Symptoms include chronic cough and shortness of breath and, occasionally, acute symptoms following heavy exposure to the offending agent.
Identifying the offending agent in these diseases can be difficult. Blood tests looking for antibodies to common offenders are done and can be helpful. X-rays and CT scans of the chest may show abnormalities, but these can often wax and wane depending on the frequency of exposure. The ultimate and usually necessary test is examination of a piece of lung tissue. Understandably, some patients are reluctant to proceed with this test which requires a surgical biopsy of the lung. The technique is done through a minimally invasive technique called thoracoscopy. The reason accurate diagnosis is important is that it involves preservation of lung function and relief of symptoms.
Once the diagnosis is established, avoidance of the offending agent is the primary treatment of choice. The patient must commit to removing the offending agent from the home completely and must seek to control the work environment as well. Frequent and long term use of drugs, such as prednisone, is not recommended.