Other Conditions That Can Cause Pain
Pain and stiffness similar to rheumatoid arthritis symptoms can be caused by many other conditions. Even if injury or infection can be ruled out, anything from bunions to fibromyalgia or chronic fatigue syndrome can cause pain.

Only a medical professional can identify many sources of joint pain, because similar symptoms can result from other autoimmune diseases, including cancer or other forms of arthritis.

The Causes of Rheumatoid Arthritis
The causes of rheumatoid arthritis are not fully understood, but important contributing factors have been identified. The self-destructive immune response of rheumatoid arthritis may be caused by a combination of genetic susceptibility and an environmental trigger. Changing hormones also may play an important part in the disease, possibly in response to an infection from the environment.

More than one gene has been linked to risk of developing rheumatoid arthritis. Specific genes may increase a person’s chance of developing the disease, and also could partially determine how serious his or her condition is. However, since not all people with a genetic predisposition to rheumatoid arthritis actually have the disease, other factors must be important.

A specific environmental trigger has not yet been found, but some research suggests that infection by a virus or bacterium can lead to rheumatoid arthritis in genetically susceptible people. This does not mean that rheumatoid arthritis is contagious. People with rheumatoid arthritis appear to have more antibodies in the synovial fluid in their joints, suggesting that there may be have been an infection.

Low levels of hormones from the adrenal gland are common in people with rheumatoid arthritis, but how hormones interact with environmental and genetic factors is unknown. Hormone changes may contribute to the progression of the rheumatoid arthritis.