The general term "arthritis" refers to a group of diseases that, in one way or another, attack the joints of the body. These attacks cause the joints to swell up and break down, resulting in pain, swelling, stiffness, fatigue, and loss of movement. There are over 100 diseases that fall into this group, but here are some of the more common ones:

Osteoarthritis - this is the most common form of arthritis. It is caused by wear and tear on a joint, due to either normal aging or by excessive strain from sports or heavy work. This condition is often seen in farmers, football players, people who have worked in manual labor jobs, and people of advancing age. Excess weight can increase the severity of this condition. Often only one joint is involved, although people who are elderly may have problems in several joints.

Rheumatoid arthritis - this disease causes a person's immune system to attack the joints, causing pain and swelling. Unlike osteoarthritis, rheumatoid arthritis affects multiple joints in the body and is known as a "systemic autoimmune" disease, as it attacks a person's system. The symptoms of rheumatoid arthritis are more noticeable in the smaller joints of the body, such as the finger, wrist, and ankle joints. This disease can onset at any age. When it occurs in a person under the age of 18, it is labeled "juvenile rheumatoid arthritis". Severe deformities in the joints can occur as this disease advances with disability resulting.

Gout - this form of arthritis causes uric acid to build up in the affected joint, causing pain, swelling, and stiffness. The big toe is the joint most often affected, but other joints may also be affected by gout. Men are affected by gout more than women and onset is most often between the ages of 50 and 60.

Lupus - Systemic lupus erythematosus, or "lupus", is another systemic autoimmune disorder, in which the immune system attacks all the parts of the body. Arthritis symptoms such as joint pain and swelling are only one component of this disorder. Although lupus is a severe disease and is historically considered fatal, recent advances in medication and treatment have increased the survival rate of people who have this disease. Lupus occurs at any age, but onset is seen most often in women.

Psoriatic arthritis - this form of arthritis occurs in people who have the skin condition psoriasis. Its symptoms are similar to rheumatoid arthritis, described above.

For more information about these and other forms of arthritis, please visit The Arthritis Foundation website at http://www.arthritis.org