Kawasaki disease is an inflammation of blood vessels that mainly affects children under 5 years old. It is the leading cause of acquired heart disease in children. While the cause is unknown, it is suspected to be a virus. If not diagnosed within 10 days of symptoms appearing, there is an increased risk of heart problems developing. The disease involves fever, rash, swelling of hands and feet, and inflammation of mucous membranes. Without treatment, 1% of children with Kawasaki disease can die from it and aneurysms in the coronary arteries can develop which may lead to heart attacks later in life.