Temporal arteritis. Light micrograph of a section through an artery affected by temporal arteritis. Temporal arteritis (Horton's disease) is a condition in which medium and large arteries, usually in the head and neck, become inflamed. The condition is one of the most common types of vasculitis (inflammation of arteries and veins). The most serious complication of temporal arteritis is permanent blindness, though this can be prevented by prompt treatment with corticosteroids. The cause is unknown but it is believed to be due in part to a faulty immune response and has been linked to severe infections and the use of high doses of antibiotics.