Arthritis, according to the Centers for Disease Control and Prevention, is "a medical condition characterized by inflammation of the joints which results in pain and difficulty moving." Arthritis is a common condition among the elderly. Over time, a swollen joint can become severely damaged. Some kinds of arthritis can also cause problems in your organs, such as your eyes or skin.
According to the National Instititute of Arthritis and Musculoskeletal and Skin Diseases, "one type of arthritis, osteoarthritis, is often related to ageing or to an injury. Other types occur when your immune system, which normally protects your body from infection, attacks your body's own tissues. Rheumatoid arthritis is the most common form of this kind of arthritis. Juvenile rheumatoid arthritis is a form of the disease that happens in children."
Other types of arthritis are Psoriatic Arthritis and lupus. In lupus arthritis is one symptom of a severe disease.