Arthritis is the inflammation of one or more joints. Symptoms of arthritis include joint pain, swelling, stiffness, and redness. There are over 100 types of arthritis. Arthritis may be triggered by injury (such as a fracture) or infection (viral, bacterial, or fungal). It may be due to gradual wear and tear on the joints or result from an autoimmune disorder. A person may have more than one type of arthritis. Arthritis affects both sexes and all ethnicities. Most types are more common in adults, but arthritis can occur at any age and can affect joints in many different parts of the body.