A chronic systemic disease, classified as a type of collagen disease or widespread pathological changes in the connective tissue; characterized by inflammatory changes throughout the body's connective tissues: Rheumatoid arthritis usually occurs during the most productive years of adulthood (ages 20 to 40), although there are some people who are affected when they are infants or even when they are much older.

The cause of rheumatoid arthritis is unknown, and there may not be one specific cause. In about 75 per cent of patients, it begins gradually, with only mild symptoms at first. These may include malaise, fever, weight loss, and morning joint stiffness.

Some bodily bone connections may become swollen, painful, and inflamed and most patients have increasingly severe and many attacks with subsequent joint damage and deformity with rheumatoid arthritis.

Besides the joint changes, rheumatoid arthritis may include atrophy of muscles, bones, and the skin adjacent to the affected bone structure or structures between the bones. The most evident lesions are subcutaneous nodules, usually over bony areas that are less protected; such as, the elbows.