Arthritis is a general term that refers to the degeneration or inflammation of a joint.
Arthritis can cause pain, stiffness and swelling in joints and other connective tissues.
According to the Institute of Aging, scientists believe there are several factors in why osteoarthritis occurs in different joints. Osteoarthritis in the knees has been linked to being overweight. Osteoarthritis in the hips or hands may be caused by heredity. Rheumatoid arthritis - Rheumatoid arthritis is an autoimmune disease that causes inflammation in the joints. Signs of rheumatoid arthritis include swelling in three or more joints, swelling of the hands or wrists, bumps under the skin and morning stiffness.