Relapsing polychondritis (RP) is characterized by recurrent swelling and inflammation of cartilage and other tissues throughout the body. Cartilage is a tough but flexible tissue that covers the ends of bones at a joint and gives shape and support to other parts of the body. Other parts of the body that may be involved are the airways (trachea), costal (rib) cartilage, eyes, heart, vascular (veins) system, skin, kidney, and nervous system. The signs and symptoms vary from person to person depending on which parts of the body are affected. The exact underlying cause of RP is unknown. There are thought to be genetic and other unknown factors involved. RP often occurs along with autoimmune conditions. Diagnosis is based on the symptoms and clinical examination. Other more common conditions may need to be excluded before RP can be diagnosed.