Giant Cell Arteritis (Temporal Arteritis)

What happens in giant cell arteritis

GCA is a form of vasculitis. Immune cells, including large "giant cells," invade the wall of arteries. The wall thickens and the channel narrows, reducing blood flow. The branches of the carotid artery in the head are most affected, including the temporal arteries at the sides of the forehead and the arteries supplying the eyes. In many patients, the aorta and its main branches are also inflamed (large-vessel GCA).

The cause is unknown. Genetic factors, aging of the immune system and possibly infections may contribute.

Symptoms

Cranial symptoms

• new headache, often at the temples, but can be anywhere
• scalp tenderness, for example when brushing hair or resting on a pillow
• jaw claudication: pain or fatigue in the jaw muscles when chewing, which eases with rest. This is one of the most specific symptoms
• tender, thickened or pulseless temporal arteries
• tongue pain or, rarely, tongue or scalp tissue damage

Eye symptoms

• sudden, painless loss of vision in one eye, often permanent
• brief episodes of blurred or lost vision (amaurosis fugax)
• double vision

Without treatment, the second eye can be affected within days.

General symptoms

• fatigue, weight loss, loss of appetite
• low-grade fever, night sweats
• depression

Large-vessel symptoms

• arm pain or fatigue when using the arms
• different blood pressure readings in the two arms
• aortic aneurysm, sometimes years later

Polymyalgia rheumatica

About half of people with GCA also have polymyalgia rheumatica, causing pain and stiffness in the shoulders, neck and hips, worst in the morning.

Diagnosis

• Blood tests: erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are raised in most patients. Normal results make GCA less likely but do not completely rule it out.
• Temporal artery ultrasound: shows a dark "halo" of wall swelling. It is increasingly used as a first test in fast-track clinics.
• Temporal artery biopsy: a small piece of artery is removed under local anesthetic. A positive biopsy confirms GCA, but it can be negative because inflammation skips segments.
• Imaging for large-vessel involvement: PET-CT, CT or MR angiography of the aorta and its branches.
• Eye examination by an ophthalmologist.

Treatment should not be delayed waiting for tests. Steroids are started as soon as GCA is strongly suspected, and biopsy or ultrasound remains informative for at least 1 to 2 weeks afterward.

Treatment

Glucocorticoids

High-dose prednisone is started immediately. People with vision loss may receive IV methylprednisolone first. The dose is reduced slowly over many months, guided by symptoms and blood tests. Most people need treatment for 1 to 2 years or longer.

Steroid-sparing treatment

• Tocilizumab, a weekly or every-other-week injection that blocks interleukin-6, reduces relapses and allows faster steroid tapering. It is approved for GCA.
• Methotrexate is an alternative.
• Upadacitinib, an oral JAK inhibitor, was approved for GCA in 2025.

Protecting against side effects

Long-term steroids cause bone thinning, diabetes, high blood pressure, weight gain, cataracts and infections. Measures include:

• calcium, vitamin D and often bone-protecting medicine to prevent osteoporosis
• monitoring of blood sugar, blood pressure and eyes
• vaccinations before or during treatment

Aspirin

Low-dose aspirin is sometimes considered to reduce the risk of stroke and vision loss, especially in people with other cardiovascular risk factors, after discussing bleeding risk.

Complications

• permanent blindness in one or both eyes
• stroke
• aortic aneurysm and dissection, so periodic aortic imaging is often recommended
• narrowing of arm arteries
• treatment-related complications from steroids

Outlook

With prompt treatment, most people's symptoms improve within days, and further vision loss is uncommon once steroids are started. Vision already lost usually does not return. Relapses are common during steroid tapering, often as headache or polymyalgia symptoms, and are treated by adjusting medicines. Many people eventually stop treatment.

Frequently asked questions

What are the first signs of giant cell arteritis?

Common early signs are a new headache, often at the temples, scalp tenderness, jaw pain when chewing, fatigue and sometimes fever or weight loss in someone over 50. Vision changes such as blurring or double vision are warning signs needing emergency care.

Is giant cell arteritis the same as temporal arteritis?

Yes. Temporal arteritis is an older name for giant cell arteritis, because the temporal arteries are commonly affected. GCA is now preferred because the disease can involve many arteries, including the aorta. See temporal arteritis for more.

Why is giant cell arteritis an emergency?

It can block blood flow to the optic nerve and cause sudden, permanent blindness, sometimes in both eyes within days. Starting high-dose steroids immediately greatly reduces this risk, which is why treatment begins before test results are back.

How long does treatment for giant cell arteritis last?

Most people take steroids for at least 1 to 2 years, starting with a high dose that is slowly reduced. Tocilizumab or methotrexate can shorten steroid use and reduce relapses. Some people need longer treatment for relapses or large-vessel disease.

What is the link between giant cell arteritis and polymyalgia rheumatica?

They are closely related inflammatory conditions of older adults. About half of people with GCA have polymyalgia rheumatica, and a smaller proportion of people with polymyalgia rheumatica develop GCA. Anyone with polymyalgia should report headaches, jaw pain or vision changes promptly.