Ask screening questions before anything else. A single missed subarachnoid haemorrhage is career-ending. Screen every new headache patient.
Subarachnoid haemorrhage carries 50% mortality and up to 46% are initially misdiagnosed in primary care — most often as migraine or tension headache. The sentinel headache ("warning leak") precedes catastrophic bleed in ~20% of cases. A thunderclap headache mandates 999 regardless of subsequent resolution.
GCA causes permanent unilateral blindness in up to 25% if untreated. Treatment must not wait for biopsy results. ESR alone is insufficient — 5% of GCA have a normal ESR; CRP is more sensitive.
NICE NG12 mandates 2WW brain tumour referral for new-onset seizure with headache, or progressive neurological deficit. Raised ICP features indicate same-day rather than 2WW.
Systematic history is your most powerful diagnostic tool. Most primary headaches are diagnosed on history alone.
Headache diaries improve diagnostic accuracy significantly and reveal medication overuse patterns invisible in consultation. Patients frequently underestimate both frequency and analgesic use. NICE NG150 recommends offering a headache diary at first presentation.
Cluster headache is the most severely painful condition known to medicine (rated >10/10 by most patients) and is frequently misdiagnosed for years as migraine or sinusitis. The restless, agitated patient who cannot lie down is pathognomonic.
Apply ICHD-3 (International Classification of Headache Disorders) criteria. Classification drives treatment — analgesic choice differs entirely between migraine and tension-type.
Medication overuse headache (MOH) affects ~1% of the UK population and is caused by overuse of triptans (>10 days/month), opioids (>10 days/month), or simple analgesics (>15 days/month). It transforms episodic migraine into chronic daily headache. The treatment is withdrawal — not escalating preventives while overuse continues. Preventives are ineffective while overuse persists.
IIH is increasing in prevalence with rising obesity rates. It causes permanent visual field loss if missed. All obese young women with daily headache deserve fundoscopy to check for papilloedema.
Examination rarely changes diagnosis in primary headaches, but is essential to exclude secondary causes and reassure patients. Document findings clearly.
Fundoscopy is the single most important examination in new headache presentations. Many GPs are deskilled — arrange ophthalmology referral if unsure of findings. Absence of venous pulsation is an early sign of raised ICP.
Normal neurological examination does not exclude a brain tumour — 40% of brain tumours present without focal signs. The combination of progressive headache + personality change + cognitive decline requires imaging even with a normal examination.
Most primary headaches require NO investigations. Over-investigation causes anxiety without benefit. Investigate only when the history or examination suggests a secondary cause.
CT sensitivity for SAH drops from 98% at 6 hours to 85% at 24 hours and 50% at 1 week. A negative CT does not exclude SAH if >6 hours post-ictus — LP is mandatory in this scenario. CTP Ottawa SAH rules can guide decision-making.
Routine neuroimaging for migraine is specifically not recommended by NICE NG150. Studies show it increases false-positive incidental findings, patient anxiety, and NHS costs without improving outcomes. Reserve CT/MRI for atypical features only.
Know your local neurology and ophthalmology pathways. Many areas now have rapid access headache clinics — check your CCB/ICB formulary.
Cluster headache is best initiated under neurological supervision. Verapamil (first-line prophylaxis, up to 480 mg/day) requires ECG monitoring before and after dose escalation due to risk of heart block. Subcutaneous sumatriptan and high-flow oxygen are the only evidence-based acute treatments.
III nerve palsy + headache mandates same-day neurosurgical assessment — a posterior communicating artery aneurysm compresses the oculomotor nerve from outside, producing a painful, pupil-involving third nerve palsy. This is a neurosurgical emergency with catastrophic rupture risk.
NICE NG12 mandates 2WW referral for progressive neurological deficit including headache. The RCP recommends urgent-access headache clinics (seen within 2 weeks) rather than A&E for urgent but non-emergency cases.
Treat the right condition. Ensure medication overuse is excluded before starting preventives. Counsel patients that preventives take 8–12 weeks to achieve full effect.
Migraine — Acute Treatment
Migraine — Preventive Treatment (≥4 attacks/month or disabling)
Tension-Type Headache — Acute
Cluster Headache — Acute (refer for confirmation)
Medication Overuse Headache — Withdrawal
Triptans are 5-HT1B/1D agonists causing vasoconstriction and blocking CGRP release. They are most effective when taken at headache onset before central sensitisation develops (do not wait for severe pain). The 24-hour rule: most triptans should not be repeated within 24 hours. Maximum 10 days/month to avoid MOH.
CGRP monoclonal antibodies represent a paradigm shift in migraine prevention — the first treatments specifically designed for migraine (not repurposed from other conditions). NHS England criteria require 4+ migraine days/month and failure of 3 prophylactics. Erenumab (Aimovig) 70 mg SC monthly is the most widely used.
Topiramate teratogenicity: Associated with oral clefts and reduced birth weight. MHRA issued a safety warning in 2023. Must not be used without effective contraception. Discuss with woman before prescribing.
Lifestyle interventions reduce migraine frequency comparably to first-line preventive drugs in trials. Address these at every appointment — not as afterthought but as core treatment.
Exercise vs topiramate (Varkey et al., Cephalalgia 2011): 3 × 40-min aerobic exercise/week was as effective as topiramate 100 mg/day in reducing migraine days (both reduced by ~2 days/month). Exercise has no side effects and positive cardiovascular, metabolic, and psychological benefits.
CBT for headache has a systematic review NNT of ~2 for clinically meaningful improvement. It is superior to pharmacological treatment for chronic daily headache and MOH because it addresses the central sensitisation and catastrophising that perpetuates chronic pain.
OCP + migraine with aura: Migraine with aura is an independent risk factor for ischaemic stroke (OR 2.2). Combined OCP further increases this risk (OR 8.7 combined). UKMEC category 4 (contraindicated). Always ask about aura before prescribing hormonal contraception.
Safety-net every patient with a clear plan. Document the safety-net advice given. Follow-up intervals depend on treatment complexity and diagnosis confidence.
Medication overuse headache develops silently — most patients are unaware they are overusing. Review headache diaries for analgesic frequency at every appointment, not just headache frequency. Once MOH is established, preventives are ineffective until overuse is stopped.
GCA relapse rate is 40–50% during prednisolone taper. Patients must know to contact GP immediately if jaw claudication or visual symptoms recur — even on treatment. Visual loss is irreversible once established.
MIDAS score is an RCGP curriculum competency — know how to use and interpret it. Score >21 = grade IV (severe disability) and supports preventive treatment and specialist referral. It is also used to demonstrate treatment response to commissioners and for CGRP criteria.