Inflammatory forms of arthritis usually involve many joints throughout the body at the same time and is caused by a problem with the immune system becoming overactive, resulting in joint inflammation. Arthritis caused by inflammation often results in pain and stiffness after periods of rest or inactivity, particularly in the morning. Swelling, redness, and warmth may be present in the affected joints. Other areas in the body can be affected by the inflammation as well, including the skin and internal organs such as the lungs and heart.
Although there are several major differences between inflammatory arthritis (IA) and osteoarthritis (OA), a major distinction is that osteoarthritis most commonly presents after the age of 50 and increases in frequency with age, while inflammatory arthritis tends to affect people of all ages, often striking people in their peak working and child-rearing age.