Approach to headache and facial pain

At a glance

• Over 90% of headaches seen in practice are primary: migraine, tension-type, cluster. The job is to find the small number that are secondary and dangerous.
• Tempo is the most useful single feature: thunderclap (seconds), acute new (hours to days), subacute progressive (weeks), or chronic recurrent (months to years).
• Use the SNNOOP10 red flags to decide who needs imaging. A normal examination doesn't exclude SAH, venous thrombosis or GCA.
• Primary headache disorders, cluster headache and medication overuse are covered in Migraine and primary headache disorders. Trigeminal neuralgia has its own note.

Causes

Tempo	Think of
Thunderclap (peak within 1 minute)	SAH, RCVS, cervical artery dissection, cerebral venous sinus thrombosis, pituitary apoplexy, intracerebral haemorrhage, colloid cyst, spontaneous intracranial hypotension
Acute, new	Meningitis or encephalitis, sinusitis, acute glaucoma, carbon monoxide, hypertensive emergency or pre-eclampsia, post-LP, first migraine
Subacute, progressive	GCA (age 50 and over), space-occupying lesion, chronic subdural haematoma, idiopathic intracranial hypertension, CVST
Chronic, recurrent	Migraine, tension-type, medication overuse headache, cluster, hemicrania continua

About 1 in 10 patients with thunderclap headache in the emergency department has SAH.

Focused history

• Onset: what were you doing, and how long to peak? Exertion, sex and Valsalva at onset raise concern for SAH and RCVS.
• Is this new or different from the usual headache? A known migraineur can still have an aneurysm.
• Position: worse lying and on waking with vomiting (raised ICP); worse within minutes of standing (low CSF pressure).
• Associated features: fever, rash, neck stiffness, seizure, confusion, visual loss, diplopia, pulsatile tinnitus, jaw claudication, scalp tenderness, proximal girdle stiffness.
• Context: pregnancy or postpartum, cancer, HIV or immunosuppression, anticoagulants, recent head or neck trauma, recent LP, chiropractic manipulation.
• Medicines: analgesic days per month (medication overuse), oral contraceptive (CVST, migraine with aura), vasoactive drugs including SSRIs, decongestants and cannabis (RCVS).
• Household: others with headache, worse in winter or at home (carbon monoxide from a faulty heater).

Focused examination

• Temperature, BP, GCS, neck stiffness and Kernig sign (absent early in SAH).
• Fundi for papilloedema and subhyaloid haemorrhage. Visual fields and acuity.
• Pupils and eye movements: a third nerve palsy with a dilated pupil suggests a posterior communicating artery aneurysm; Horner syndrome with neck pain suggests carotid dissection.
• Temporal arteries (tender, thickened, pulseless), scalp tenderness.
• Full neurological examination for focal signs.
• Red eye with a mid-dilated, fixed pupil and halos: acute angle-closure glaucoma.

Red flags

SNNOOP10 (Do et al., 2019):

Flag	Examples
Systemic symptoms	Fever, weight loss
Neoplasm history	Known cancer
Neurological deficit or dysfunction	Focal signs, confusion, seizure
Onset sudden	Thunderclap
Older age	New headache after 50
Pattern change or recent onset	Progressive, change in a known headache
Positional	Worse lying or standing
Precipitated by sneeze, cough or exercise	Valsalva headache: posterior fossa lesion, Chiari
Papilloedema	Raised ICP
Progressive and atypical presentations
Pregnancy or puerperium	Pre-eclampsia, CVST, RCVS, apoplexy
Painful eye with autonomic features	Glaucoma, cluster mimics
Post-traumatic	Subdural haematoma
Pathology of the immune system	HIV, transplant: cryptococcus, toxoplasma, lymphoma
Painkiller overuse or new drug	Medication overuse, drug side effect

Investigations

Suspected subarachnoid haemorrhage

• Apply the Ottawa SAH rule to alert patients aged 15 or over with a new severe non-traumatic headache peaking within an hour. It is near 100% sensitive but only about 15% specific, so it rules out rather than rules in.
• Non-contrast CT within 6 hours of onset, read by an experienced radiologist, is close to 100% sensitive in a neurologically normal patient (Perry, BMJ 2011). A normal scan here rules out SAH.
• After 6 hours: CT sensitivity falls. Do an LP at least 12 hours after onset and look for xanthochromia. CT angiography is an accepted alternative in many centres, accepting that it finds small incidental aneurysms.
• Confirmed SAH: CTA for the aneurysm, nimodipine 60 mg every 4 hours for 21 days, and early aneurysm securing (AHA/ASA 2023).

Pitfall: a falling red cell count from tube 1 to tube 4 doesn't reliably exclude SAH. Xanthochromia does the work.

Other targeted tests

Suspicion	Test
GCA	ESR and CRP (CRP is the more sensitive), FBC (thrombocytosis); temporal artery ultrasound (halo sign) as soon as possible, ideally within a few days of starting steroids, as the temporal halo shrinks over the first week (axillary changes persist longer); biopsy within about 1 to 2 weeks
CVST	CT or MR venography. D-dimer can be normal
Dissection	CTA or MRA of the neck
Meningitis	Blood cultures, then LP. CT first only if reduced GCS, focal signs, papilloedema, seizure or immunocompromise
Raised ICP or mass	MRI with contrast. LP opening pressure (after imaging) for IIH: 25 cmH2O or more in adults
Spontaneous intracranial hypotension	MRI brain with contrast, then spinal imaging for the leak
Carbon monoxide	Carboxyhaemoglobin on a venous or arterial gas
Pituitary apoplexy	Hydrocortisone immediately if unwell (cortisol drawn first if no delay), then MRI pituitary

• Don't image typical migraine or tension-type headache with a normal examination. The yield is below that of incidental findings.
• In pregnancy, use MRI without gadolinium. CT of the head gives a negligible fetal dose and shouldn't be withheld in an emergency.

Management of the important secondary causes

• GCA: start prednisolone 40 to 60 mg daily (about 1 mg/kg) the same day on clinical suspicion. With visual symptoms, give IV methylprednisolone. Tocilizumab is the main steroid-sparing agent. Polymyalgia symptoms occur in about half.
• CVST: risks are pregnancy and the puerperium, oestrogen, thrombophilia, dehydration, infection and cancer. Anticoagulate with LMWH or heparin even when there is venous haemorrhage. DOACs are an accepted alternative after the acute phase (ACTION-CVT, RE-SPECT CVT).
• RCVS: recurrent thunderclap headaches over 1 to 2 weeks, often postpartum or after serotonergic or sympathomimetic drugs. Angiographic "string of beads" resolves within 3 months. Stop the trigger, use nimodipine for symptoms, and avoid triptans and glucocorticoids (steroids are linked to worse outcomes).
• Idiopathic intracranial hypertension: usually women of childbearing age with obesity. Papilloedema threatens vision. Weight loss (IIH:WT trial), acetazolamide, and urgent ophthalmology. Exclude CVST with venography.
• Post-LP headache: use an atraumatic needle to prevent it. Fluids and caffeine help little. An epidural blood patch is the definitive treatment if it persists.
• Hypertensive headache needs a very high BP: ICHD-3 uses systolic 180 mmHg or more and/or diastolic 120 mmHg or more, usually as a hypertensive crisis. Don't blame moderate hypertension for a headache.

Acute migraine in the emergency department

• Prochlorperazine 10 to 12.5 mg IV or metoclopramide 10 mg IV with IV fluids. Chlorpromazine is an alternative (watch for hypotension).
• Sumatriptan 6 mg SC if no vascular contraindication.
• Greater occipital nerve block with local anaesthetic is a "must offer" option in the 2025 AHS guideline.
• Avoid opioids. The 2025 AHS guideline says hydromorphone must not be offered. Opioids increase return visits and drive medication overuse.
• Dexamethasone 10 mg IV reduces headache recurrence over the next 72 hours.

Facial pain

Cause	Clues
Trigeminal neuralgia	Seconds-long electric shocks in V2 or V3, triggered by touch, chewing or brushing teeth
Post-herpetic neuralgia	Continuous burning pain with allodynia, usually V1, after shingles
Dental	Pain on biting, thermal sensitivity, localised tenderness
Temporomandibular disorder	Pain in front of the ear on chewing, jaw clicking, bruxism
Acute sinusitis	Pain over the sinus, purulent discharge, worse bending forward. Chronic headache is rarely sinus disease
GCA	Jaw claudication in someone over 50
Cluster and other TACs	Orbital pain with tearing, rhinorrhoea, ptosis
Glossopharyngeal neuralgia	Throat and ear pain on swallowing, sometimes with syncope
Persistent idiopathic facial pain	Daily poorly localised pain, normal examination: a diagnosis of exclusion

Pitfalls

• Neck stiffness is often absent in the first hours of SAH. Don't rely on it.
• Analgesic response doesn't separate benign from dangerous headache. SAH pain can ease with paracetamol or a triptan.
• "Migraine" first appearing after 50 is GCA, a mass or a subdural haematoma until proven otherwise.
• A third nerve palsy with pupil involvement is an expanding aneurysm until CTA shows otherwise.
• Carbon monoxide gives a normal oxygen saturation on pulse oximetry. Ask who else at home is unwell.
• A normal CT doesn't exclude CVST, dissection, RCVS, IIH or meningitis.
• Headache with new or uncontrolled hypertension after 20 weeks' gestation or in the first weeks postpartum is pre-eclampsia until proven otherwise, and eclampsia can occur up to 6 weeks postpartum.