Most headaches earn patience. You take something, you lie down in a dark room, you wait. There is one headache that arrives in your fifties, sixties or seventies and earns exactly the opposite response, and the gap between those two reactions is sometimes a week of eyesight.
Giant cell arteritis is inflammation of the medium and large arteries, most famously the ones running just under the skin of your temples. It is the commonest form of vasculitis in older adults, almost never diagnosed under 50, and most common in people over 70. It is also one of the very few conditions where the correct order of events is to start the treatment first and confirm the diagnosis afterwards. That reversal is not a shortcut. It is the entire point.
TL;DR
- Giant cell arteritis (GCA, once called temporal arteritis) causes a new headache, scalp tenderness, jaw pain on chewing and, at worst, sudden permanent sight loss. It occurs almost exclusively in people over 50.
- Untreated, once one eye is affected, up to half of people lose sight in the second eye within days. Guidelines say suspected GCA should reach a specialist ideally the same working day, and within three working days in every case. New visual loss or double vision means an ophthalmologist the same calendar day.
- High-dose steroids are started on suspicion, before any test confirms anything. A Royal Victoria Eye and Ear Hospital study in Dublin found that early steroids did not affect biopsy results, so there is no reason to wait.
- Ireland has no HSE Health A to Z page for GCA, no published national fast-track pathway and no registry. On CSO population figures and international incidence rates, roughly 200 to 570 people here develop it every year.
- Supports: Arthritis Ireland helpline 0818 252 846 (Monday to Friday, 10am to 4pm) and Vasculitis Ireland Awareness, which meets in Dublin and Belfast.
Why the clock is the whole story
The arteries GCA inflames include the ones feeding the optic nerve. When inflammation closes those vessels off, the nerve is starved, and the sight that goes does not come back. No operation or drug restores it. What treatment protects is everything you still have: if one eye has already been affected and nothing is done, up to half of people lose vision in the other eye within days, sometimes within 24 to 48 hours. Prompt high-dose steroids very nearly abolish that second-eye risk, which is why guidelines here read less like clinical advice and more like a fire drill.
The British Society for Rheumatology guideline, which Irish clinicians work from in the absence of an Irish one, puts it plainly: suspected GCA should reach a specialist ideally the same working day, and in all cases within three working days. Anyone reporting new visual loss, even temporary, or new double vision should see an ophthalmologist the same calendar day.
The symptoms that do not announce themselves as a headache
The textbook version is a new, persistent headache over one or both temples, often with a scalp that hurts to touch, so that brushing your hair or resting your head on a pillow becomes unpleasant. The artery itself may feel thickened, tender or oddly pulseless.
The most telling symptom, though, is the one people rarely think to mention. Jaw claudication is aching or cramping in the jaw muscles that comes on while chewing and eases when you stop, because the muscles are not getting enough blood. In studies of people sent for biopsy, it raised the odds of a positive result roughly ninefold. People describe giving up on steak, or stopping halfway through a sandwich, and almost nobody volunteers this at an appointment unless asked.
Fever, weight loss, night sweats, fatigue and the shoulder and hip stiffness of polymyalgia rheumatica belong to the picture too. In one Dublin hospital series, 87% reported headache, 73% had vision problems and 60% had polymyalgia symptoms.
Two traps are worth naming. Some people have GCA with no headache at all, presenting instead with weeks of feeling unwell. And blood tests are not a safety net: up to around 13% of people have a normal or low CRP and about 17% a normal ESR, and their risk of sight loss is no lower.
Three doors, three of Ireland’s longest queues
GCA knocks on whichever door matches its loudest symptom. Headache suggests neurology. Lost vision suggests ophthalmology. Aching shoulders and hips suggest rheumatology. Each is a logical referral, and each is the wrong route.
The National Treatment Purchase Fund publishes Ireland’s outpatient waiting lists as open data. At the end of August 2026, the adult ophthalmology list held 41,701 people, of whom 4,874 had waited more than 18 months. Neurology held 27,451. Rheumatology held 17,017. Set those against a target measured in working days and the arithmetic does itself: a routine referral letter is not a slow version of the right answer here, it is a different answer entirely. Suspected GCA belongs in a same-day phone call from your GP to the on-call medical or ophthalmology team, or, if vision is affected, in an emergency department.
The part that surprises people: treatment comes first
We expect medicine to test, then treat. GCA inverts it. Guidelines recommend starting 40 to 60mg of oral prednisolone daily as soon as GCA is strongly suspected, at the higher end of that range for anyone with jaw or tongue claudication or visual symptoms, and letting the confirmatory tests follow.
Understandably, people worry that steroids will wash away the evidence. A 2025 study from the Royal Victoria Eye and Ear Hospital in Dublin, published in the Irish Journal of Medical Science, looked at exactly this. Across 56 patients who had both an ultrasound and a temporal artery biopsy, steroids were started in 90%, and the timing did not affect the biopsy result. Starting early, the authors concluded, is safe and effective, and it does not cost you the diagnosis.
That same study contains a number worth sitting with: the biopsy confirmed GCA in 53% of cases. Nearly half the people started on high-dose steroids on suspicion turned out not to have it. That is not a failure. It is the system working as designed, because the price of waiting to be certain is paid in eyesight, and it is not refundable.
Ultrasound or biopsy? A Dublin hospital counted
Across Europe, many centres now lead with ultrasound of the temporal and axillary arteries, looking for the “halo sign” of a thickened, inflamed vessel wall, keeping biopsy for when the scan is negative or unclear. The Dublin findings were more cautious. Against biopsy, Doppler ultrasound showed 70% sensitivity and 53% specificity, and the authors concluded that biopsy remains crucial for confirmation. Everyone in that group had both tests, which selects for the harder cases, so this is not a verdict on ultrasound everywhere. But if you are offered a scan here and it comes back clear while your symptoms persist, a normal ultrasound is not the end of the conversation. Ask whether a biopsy is still warranted. One practical note: the halo starts shrinking within the first week of steroids, so the imaging needs to be arranged quickly rather than casually.
Delay is well measured in this condition. A meta-analysis pooling 16 studies found a mean of 9.0 weeks between first symptom and diagnosis: 7.7 weeks for the classic cranial picture, 17.6 weeks without it. Geography compounds it. A 2025 analysis of 317 people with GCA found living rurally was the single strongest predictor of delay, at a mean of 130 days to diagnosis against 45 days for those closer to services. That was American data, but in a country where specialist vasculitis clinics cluster around a handful of cities, the relevance is not hard to see.
Living on steroids, honestly
Getting the diagnosis right is the beginning, not the end. GCA treatment is a long taper measured in many months, often a couple of years, and relapse is common: around 32% within the first year and 44% within two. Long courses of prednisolone bring their own bill, including bone loss, raised blood sugar, thinner skin, weight gain, cataract, disturbed sleep and low mood, which is why bone protection and monitoring should be discussed at the start rather than improvised later.
A 2026 qualitative study of 20 people recently diagnosed with GCA, median age 68, found the dominant themes were not clinical at all: uncertainty and fear, a changed sense of self, lost autonomy, and how much each healthcare conversation mattered. If that is where you are, it is a normal reaction and worth naming to your team.
A new option, and a decision Ireland has not made
Steroid-sparing treatment has moved quickly. Upadacitinib, an oral JAK inhibitor, was approved by the European Commission for GCA in April 2025 on the strength of the SELECT-GCA trial, where 46.5% of participants achieved sustained remission against 29.0% on placebo. It is the second licensed treatment for GCA after tocilizumab.
A European licence is not Irish access. The National Centre for Pharmacoeconomics opened its assessment (HTA ID 25023) in March 2025 and completed a rapid review that April, recommending a full health technology assessment. As of the end of September 2026, that is still where the file sits: seventeen months on, reimbursement here has not been decided.
It is part of a wider quiet. The HSE’s Health A to Z runs to 483 entries and includes no page for giant cell arteritis, temporal arteritis, polymyalgia rheumatica or vasculitis. England and Wales audit GCA care nationally; Ireland publishes no equivalent, no national fast-track pathway and no registry, which is why the case numbers in this article had to be estimated rather than looked up. Applying international incidence rates of 10 to 30 per 100,000 people aged 50 and over to the 1.91 million people in that age group here (CSO, April 2026) gives roughly 200 to 570 new cases a year: somewhere between four and eleven people every week, uncounted.
What to do if you recognise yourself here
If you are over 50 and have a new headache unlike your usual ones, particularly with a tender scalp, jaw pain on chewing, or any change in vision, contact your GP today and use the words “I am worried this could be giant cell arteritis.” Naming it shifts the appointment from routine to urgent.
If vision has already blurred, dimmed, doubled or gone, even briefly and even if it came back, that is an emergency department visit now. Ask whether steroids should be started today rather than after the tests, and how quickly the ultrasound or biopsy can be arranged. If you are put on prednisolone, ask about bone protection and a written tapering plan before you leave.
Where to turn
Arthritis Ireland runs a national helpline on 0818 252 846, Monday to Friday from 10am to 4pm, or [email protected]. Vasculitis Ireland Awareness supports people across the island with GCA and other vasculitis conditions, holds meetings in Dublin and Belfast, runs a one-to-one “Link Up” peer service, and can help you find the nearest specialist vasculitis clinic. They can be reached on 075 22932126 from Northern Ireland, or 0044 75 22932126 from the Republic.
At Críonna Health we write a great deal about ageing well, and most of it concerns the slow work of habits built over years. This is the exception. Giant cell arteritis is one of the few conditions where a decision taken on a single afternoon changes the rest of your life, and almost all the power in that decision belongs to whoever notices the symptom first. Usually that is you.
This article is for general information and is not a substitute for individual medical advice. If you are concerned about your symptoms, contact your GP or, in an emergency, call 112 or 999.
📷 Photo by Ariel Salgado on Unsplash
