What is arthritis?
Arthritis is an inflammation of the joints. It can affect one joint or several joints. There are more than 100 different types of arthritis with different causes and methods of treatment. Two of the most common types are osteoarthritis (OA) and rheumatoid arthritis (RA).
Symptoms of arthritis usually develop over time, but they can also appear suddenly. Arthritis most often occurs in adults over 65 years, but can also develop in children, adolescents, and younger adults. Arthritis is more common in women than in men and in obese people.