Osteoarthritis, also known as degenerative joint disease (DJD), happens when cartilage is worn down over time, usually from a lifetime of use or as the result of an injury to the joint. As the normally smooth surface of the cartilage is destroyed, exposing the underlying bone, the joint becomes more painful to move and the range of motion may diminish. This type of arthritis usually involves one or more large weight-bearing joints such as a hip or a knee. With this type of arthritis, pain is usually made worse with activity and is better with rest. It is common for symptoms to be at their worst at the end of the day.
Less frequent but often more serious are the inflammatory forms of arthritis, which include conditions such as rheumatoid arthritis and lupus. These forms 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.