Caplan syndrome is swelling (inflammation) and scarring of the lungs in people with rheumatoid arthritis who have been exposed to mining dust, such as coal, silica, or asbestos.

Caplan syndrome is caused by breathing in mining dust, which causes inflammation and can lead to the development of many small lung bumps (nodules) and mild asthma-like airway disease.

Some people who have been exposed to the dust have severe lung scarring that makes it difficult for their lungs to carry oxygen to the bloodstream (called progressive massive fibrosis). People with rheumatoid arthritis do not seem more likely to have this complication of scarring. Caplan syndrome is very rare in the United States.

• Cough
• Shortness of breath
• Wheezing
• Nodules of the skin (rheumatoid nodules)
• Joint swelling and pain

Your health care provider will take a detailed medical history that will include questions about your jobs (past and present) and other possible sources of exposure to mining dust. The health care provider will also do a physical exam, paying special attention to the presence of joint and skin disease.

Other tests can include:

• Chest x-ray
• Joint x-rays
• Pulmonary function tests
• Rheumatoid factor titer test