Farmer's lung history and symptoms

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Shaik Aisha sultana, [2]

There is no single, simple test to distinguish between Farmer’s Lung and other types of lung diseases. The most important evidence for Farmer’s Lung is the history of exposure to dust from moldy hay or other moldy crops and the development of signs and symptoms 4 to 8 hours later. This is why it is so important for a doctor to know if a patient with shortness of breath has been exposed to moldy crops.

There is no single, simple test to distinguish between Farmer’s Lung and other types of lung diseases. The most important evidence for Farmer’s Lung is the history of exposure to dust from moldy hay or other moldy crops and the development of signs and symptoms 4 to 8 hours later. This is why it is so important for a doctor to know if a patient with shortness of breath has been exposed to moldy crops.

The signs and symptoms of Farmer’s Lung disease vary tremendously. At one extreme, there are the symptoms associated with a sudden attack; at the other extreme, there are the symptoms associated with a slow progressive illness.

The allergic response of the afflicted person depends on the sensitivity of the individual and the amount of moldy dust entering the lungs. There are three different types of allergic responses: acute or intense attack, sub-acute or low-level response, and chronic or long-term response.

Acute Farmer’s lung is easy to notice and occurs in about one in three cases. It starts as an intense attack about 4 to 8 hours after the person breathes in a large amount of dust from moldy crops. These are some of the signs and symptoms:

• Shortness of breath
• A dry irritating cough
• A sudden general feeling of sickness(malaise)
• Fever and chills
• A rapid heart rate
• Rapid breathing
• Myalgia

If the person avoids further exposure to moldy dust, the signs and symptoms usually decrease after 12 hours, but they can last up to two weeks. Serious attacks can last as long as 12 weeks. The symptoms are sometimes confused with pneumonia.

Sub-acute Farmer’s lung is more common than acute Farmer’s Lung but it is less intense and more difficult to notice. It develops slowly, responding to continual exposure to small amounts of moldy dust. The signs and symptoms include:

• Coughing
• Shortness of breath
• A mild fever and occasional chills
• A general feeling of sickness
• Aches and pains in the muscles and joints (arthralgia and muscle ache)
• A loss of appetite and loss of weight

People who are sensitive to dust from moldy crops continue to exhibit these signs and symptoms as long as they are exposed to the dust. This condition sometimes resembles a “chest cold” that lingers throughout the winter. Some people lose weight over several weeks.

Chronic Farmer’s lung develops after several acute attacks over a period of years. It afflicts people who have been continually exposed to large amounts of moldy dust.

Sometimes, the illness lasts several months and is marked by increasing:

• Shortness of breath
• An occasional mild fever^[1]
• Often, a significant loss in weight
• A general lack of energy(fatigue)

The symptoms are accompanied by permanent lung damage and gradually worsen as exposure to moldy dust continues.