Giant cell arteritis (GCA) is inflammation of the blood vessels. It is also called temporal arteritis. It mostly affects the arteries that carry blood to the head, especially those that supply the eyes, temple, and jaw. The most common symptom is a new headache, often near the temple or around the eye.
GCA is treated with steroid medicines, which reduce inflammation. If GCA is not treated right away, it can cause loss of vision.
Some people who have giant cell arteritis also have polymyalgia rheumatica. This is another inflammatory condition that affects the muscles.