Giant Cell Arteritis (previously known as Temporal Arteritis) is a vascular disease characterized by inflammation of blood vessels. It can cause a very severe headache that usually strikes people over age 55. The pain is in the temple, and vessels in that area can be tender. In some cases, patients may have other bodily symptoms such as fever, loss of appetite or joint and muscle pain. This is sometimes called Polymyalgia Rheumatica.

The diagnosis is based on history, examination, and diagnostic tests. The first test that needs to be done in this disorder is a Westergren Method Sedimentation Rate (sed rate). The sed rate and CRP is usually high in Giant Cell Arteritis, but in some cases can be normal. The key test to rule it in or out is a biopsy of the temporal artery. Most physicians are familiar with this condition, but rheumatologists may specialize in its treatment.

It is very important that the patient receive immediate treatment because Giant Cell Arteritis can lead to blindness.