Leukocytoclastic vasculitis, also called hypersensitivity vasculitis, describes inflammation of small blood vessels. The term leukocytoclastic refers to the debris of neutrophils (immune cells) within the blood vessel walls. The disease can be confined to the skin (cutaneous) or it can affect many different organs of the body such as the kidneys, central nervous system, heart, gastrointestinal tract, and lungs. An allergic reaction to drugs, food, or food additives supports the theory of the immune system playing the dominant role. Infections, inflammatory bowel disease, rheumatoid arthritis, lupus erythematosus, Sjögren syndrome, and less often malignancy are some of the various conditions associated with the vasculitis. In the skin, damaged blood vessels become leaky and small areas of hemorrhage appear as purple-red, raised lesions known as palpable purpura. Multiple discrete or grouped lesions are commonly found on the legs or other dependent areas of the body. These lesions are usually asymptomatic but can be itchy or painful. Signs of systemic involvement include fever, muscle aches, joint pain, blood in the urine or stool, abdominal pain, vomiting, cough, numbness, and weakness.