Rheumatoid arthritis can affect systems in the body apart from the joints.

In the skin, small lumps may develop, particularly on the outside surfaces of joints. These are called rheumatoid nodules and are caused by the inflammatory process. They occur in around 20% of cases of rheumatoid arthritis.

In about 15% of cases, rheumatoid arthritis is part of a condition called Sjögren’s syndrome. This is the name used to describe the combination of dry eyes, dry mouth and rheumatoid arthritis. It occurs when the tear and salivary glands become infiltrated by inflammatory cells. Scleritis (painful, red eye) can also occur.

The inflammatory process of rheumatoid arthritis can affect the lungs in a number of ways. The most common are pleural effusion (water on the lung), pulmonary fibrosis (the development of scar tissue in the lungs) and rheumatoid nodules in the lungs.

People with rheumatoid arthritis have a higher than usual risk of developing cardiovascular diseases such as atherosclerosis (hardening of the arteries), heart attack or stroke.

Rheumatoid arthritis can cause an abnormal protein called amyloid to build up in the kidneys, affecting their normal function.