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Health condition · Clinically reviewed

Giant cell arteritis, a same-day steroid emergency to protect vision.

Large-vessel vasculitis of the temporal arteries — untreated it causes blindness. High-dose steroid is started before biopsy confirmation.

Jump to treatment See red flags
A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Every claim is checked against BSR, NICE and EULAR guidance you can see at the end.

  • 03

    Current for 2026

    Reflects current UK guidance on same-day steroid, ultrasound halo sign and tocilizumab.

Key facts

Giant cell arteritis at a glance.

The essentials, in plain English — what GCA is, why it threatens vision, and how it is diagnosed and treated in the UK today.

  • Definition

    Large-vessel granulomatous vasculitis of the temporal and cranial arteries — inflammation narrows the vessel wall and can cut off blood to the eye.

  • Who it affects

    Almost always over 50 — peak in the 70s — and around two to three times more common in women than men.

  • Vision-threatening

    Ischaemic optic neuropathy can cause sudden, permanent blindness — the risk is why treatment starts before biopsy.

  • Classic bloods

    High CRP and ESR alongside new temporal headache and jaw claudication is the textbook trio.

  • How it’s confirmed

    Ultrasound of the temporal artery (halo sign) or temporal artery biopsy — biopsy remains the reference standard.

  • Steroid-sparing

    Tocilizumab is now used to reduce cumulative steroid dose and prevent relapse in eligible patients.

Why this guide matters

Sight can be saved in hours.

The hours between first symptom and first steroid dose decide whether vision is preserved — this is one of the few true rheumatology emergencies.

  • Treat first, confirm second

    High-dose steroid is started the moment GCA is suspected — biopsy still shows the changes days later.

  • Fast-track pathways work

    Ultrasound halo sign in expert hands allows same-day diagnosis without waiting weeks for biopsy.

  • Steroid-sparing has arrived

    Tocilizumab means less cumulative steroid and fewer of the long-term side-effects that used to define GCA care.

How the diagnosis is made

From first temporal headache to a clear plan.

The same-day steps a UK GP, rheumatology and ophthalmology team will normally take, in order — so you know what to expect and why.

  1. 01

    Recognising

    Same-day recognition of features

    New temporal headache, jaw claudication or visual change over 50 — treat as GCA until proven otherwise.

  2. 02

    Recognising

    CRP, ESR and full blood count

    Very high inflammatory markers support the diagnosis — a normal CRP makes GCA unlikely.

  3. 03

    Recognising

    Ultrasound temporal artery

    The halo sign (hypoechoic vessel wall thickening) is diagnostic in expert hands and available same-day in fast-track clinics.

  4. 04

    Confirming

    Temporal artery biopsy

    Ideally within 2 weeks of starting steroid — a 1–2 cm segment showing granulomatous inflammation confirms the diagnosis.

  5. 05

    Confirming

    MRA or PET-CT for large vessels

    Looks for aortitis and involvement of the subclavian, axillary or vertebral arteries in atypical presentations.

  6. 06

    Confirming

    Rheumatology and ophthalmology

    Urgent same-day referral — ophthalmology reviews the visual pathway; rheumatology leads long-term care.

  7. 07

    Treat

    Start high-dose steroid immediately

    Do not wait for biopsy or scan — a dose of prednisolone before investigations protects the eye.

Typical timeline: same day from suspicion to first steroid dose.

Symptoms

What giant cell arteritis actually feels like.

A new temporal headache in someone over 50, jaw pain on chewing and any visual change — together, these are a rheumatology emergency.

  • New temporal headache over 50

    A new, persistent one-sided headache over the temple in someone over 50 is the classic opening symptom.

  • Jaw claudication

    Aching in the jaw muscles while chewing — highly specific for GCA and often the most telling symptom.

  • Scalp tenderness

    Pain on brushing the hair or resting on a pillow — the scalp arteries are inflamed and tender.

  • Visual loss or double vision

    Amaurosis fugax (transient blackout), sudden loss of vision or diplopia — treat as a sight-threatening emergency.

  • Polymyalgia rheumatica features

    Shoulder and hip-girdle stiffness overlaps with GCA in around half of patients.

  • Temporal artery tenderness

    The artery may be thickened, tender or without a pulse on examination.

  • Constitutional symptoms

    Fever, night sweats, fatigue and weight loss point to systemic large-vessel inflammation.

  • Red flag

    Acute vision loss — call 999. Immediate high-dose steroid is needed to save sight in the other eye.

Treatment

How giant cell arteritis is treated in the UK.

A same-day layered approach: high-dose steroid first, tocilizumab or methotrexate to spare steroid, and bone, gastric and vascular protection alongside.

  • Prednisolone 40–60 mg (uncomplicated)

    Started the moment GCA is suspected, before biopsy — the single most important step to protect vision.

  • IV methylprednisolone (visual involvement)

    Pulsed intravenous steroid for 3 days when there is visual loss or diplopia, followed by high-dose oral prednisolone.

  • Tocilizumab (steroid-sparing)

    An IL-6 blocker given weekly — reduces cumulative steroid dose and prevents relapse in eligible patients.

  • Methotrexate

    A traditional steroid-sparing option used when tocilizumab is not suitable or available.

  • Bone protection

    Bisphosphonate with calcium and vitamin D from day one — long-term steroid drives osteoporosis.

  • Gastric protection

    A proton pump inhibitor while on high-dose steroid protects against gastric ulceration.

  • Aspirin in specific cases

    Low-dose aspirin is considered where there is ischaemic risk — decision made by the rheumatology team.

  • Slow steroid taper

    Prednisolone is weaned over 12–24 months guided by symptoms and CRP — most relapses happen during taper.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP, rheumatology or ophthalmology team knows your history and can tell you which parts apply to you. If in doubt, get seen the same day.

  • British Society for Rheumatology. Guideline on the diagnosis and treatment of giant cell arteritis.

  • NICE. Giant cell arteritis (NG201) and PMR/GCA CKS.

  • EULAR. 2018 recommendations for the management of large-vessel vasculitis.

  • PMR & GCA UK. Patient information and support.

Red flags

When giant cell arteritis becomes an emergency.

GCA is a rheumatology emergency in itself — these are the situations that demand same-day action or a 999 call.

  • Acute vision loss

    Sudden loss of vision in one eye — call 999. Immediate IV steroid can protect the other eye.

  • Diplopia

    New double vision in someone with suspected GCA is a warning of impending optic ischaemia.

  • Amaurosis fugax

    A transient blackout of vision, like a curtain — needs same-day steroid and ophthalmology review.

  • Stroke

    GCA can involve the vertebral and carotid arteries — new focal neurology is a stroke call.

  • Large-vessel involvement

    Aortitis can cause aneurysm and dissection — new back or chest pain deserves urgent imaging.

  • Steroid osteoporotic fracture

    Sudden back pain or loss of height on long-term steroid — arrange spinal imaging and DEXA.

  • Post-steroid diabetes

    Thirst, polyuria or blurred vision on high-dose steroid — check a random glucose and HbA1c.

  • Immunosuppression infection

    Fever, new cough or shingles on steroid or tocilizumab — contact your team the same day.

  • Relapse on taper

    Return of headache, jaw claudication or a rising CRP as steroid is weaned — dose needs to go back up.

Living with it

A long course of steroid, but a very manageable one.

Four things that make the biggest difference day to day — movement, a flare plan, nutrition, and regular CRP checks.

A quiet reminder

Never stop steroid suddenly.

After weeks of prednisolone your adrenal glands need a slow, guided taper — abrupt stopping is dangerous.

  1. 01 Movement

    Keep moving on steroids

    Weight-bearing exercise protects bone and muscle during long steroid courses.

  2. 02 Flares

    Know the warning signs

    Any return of headache, jaw or visual symptoms during taper needs same-day contact with your team.

  3. 03 Nutrition

    Bone and blood sugar

    Calcium-rich diet, vitamin D and low added sugar reduce two of the biggest steroid side-effects.

  4. 04 Reviews

    Regular CRP monitoring

    Blood tests every few weeks during taper catch relapse before the eye is at risk.

Frequently asked

Everything we get asked about giant cell arteritis.

Quick answers on diagnosis, the halo sign, why steroid comes before biopsy, tocilizumab and taper length.

  • What is giant cell arteritis?

    Giant cell arteritis is a large-vessel granulomatous vasculitis affecting people over 50. It inflames the temporal and cranial arteries and, if untreated, can cause sudden permanent blindness.

  • How is giant cell arteritis diagnosed?

    By clinical features (new temporal headache, jaw claudication, visual symptoms), raised CRP and ESR, temporal artery ultrasound (halo sign) and temporal artery biopsy — often supported by MRA or PET-CT.

  • Why is steroid started before the biopsy?

    Because vision loss in GCA is sudden and permanent. High-dose prednisolone is started the moment GCA is suspected — the biopsy still shows the changes if done within about two weeks.

  • What is the halo sign?

    On ultrasound of the temporal artery, the halo sign is a dark rim of wall oedema around the vessel lumen. In expert hands it is highly specific for GCA and allows same-day diagnosis.

  • What is tocilizumab and who gets it?

    Tocilizumab is an IL-6 receptor blocker given weekly by injection. It is used as a steroid-sparing agent in relapsing or refractory GCA and reduces the total steroid dose needed.

  • How long is steroid treatment?

    Most people take prednisolone for 12 to 24 months on a slow taper. Bone protection, gastric protection and CRP monitoring run alongside for the whole course.

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