There are five common forms of arthritis, which include: osteoarthritis, rheumatoid arthritis, psoriatic arthritis, gout, and lupus. Typically, arthritis is usually diagnosed between the ages of thirty to fifty years of age, although this can vary given the different types of arthritis. While arthritis is an illness that is usually associated with growing older, it is possible for children to develop the disease. The most common form of arthritis in children is juvenile idiopathic arthritis, or JIA, which is also known as childhood arthritis or juvenile rheumatoid arthritis.