Headache is a common problem in our daily life. Usually people go to neurology for headaches, but there is a type of headache that needs to be seen in rheumatology, called “temporal arteritis (giant cell arteritis)”, which is a vasculitis and a rheumatic immune disease that affects older people, especially those over 50 years old, and is more common in women than men. It often affects the carotid system and is particularly prone to invade the cranial arteries. Aortic segments and their branches, coronary arteries and peripheral arteries. The typical symptom is severe headache, and the headache is often the earliest manifestation. Patients have a vivid memory of the timing of the headache, which can be detailed to a particular day of the year. The headache is usually unbearable with constant attacks of throbbing pain that can spread throughout the head. There may be pressure pain in the temporal region (temples) and occipital region, and in severe cases, the scalp may feel particularly painful when combing the hair. In addition to headaches, temporal arteritis can also affect vision and can have transient blackness, diplopia, blind spots, ptosis, and decreased vision. If left untreated, some patients suffer from blindness due to optic nerve ischemia. In addition, pain during chewing of the occlusal, temporal and lingual muscles is a characteristic manifestation of temporal arteritis. Patients with temporal arteritis are often associated with rheumatic polymyalgia, and will have muscle and joint pain, unexplained fever, unexplained weight loss, and anxiety. The greatest danger of temporal arteritis is blindness. To prevent blindness, once the diagnosis of temporal arteritis is suspected, the diagnosis should be confirmed and treated aggressively at the Department of Rheumatology and Immunology immediately. Therefore, elderly people with unexplained headache should seek medical attention promptly and not ignore the diagnosis of rheumatologic immune disease to reduce disability.