Giant cell arteritis (temporal arteritis)
Giant cell arteritis, or GCA, affects the large arteries that supply the head and neck, especially the temporal artery which is found over the temples. There are around 5,000 new cases a year in the UK and it's more common in northern Europe. GCA doesn't normally affect people below the age of 50.
GCA can cause headaches and is often associated with a condition called polymyalgia rheumatica (PMR), which causes inflammation and stiffness in the muscles of the shoulders and hips.
GCA occasionally involves the blood supply to the eye, where it can cause blindness. If you develop symptoms in your eyes, such as blurring or double vision, you should see your doctor straight away as you'll need to be treated urgently.
Other blood vessels, such as the major arteries, can less commonly be involved in GCA.
For more information, see giant cell arteritis.