Headache — Types, Causes & When It's a Medical Emergency — Causes, Diagnosis & When to See a Doctor | MyMedicPlus

Headache is one of the most prevalent neurological disorders worldwide, affecting approximately 50% of adults in any given year and approximately 15% of people on any single day. According to the Global Burden of Disease study, headache disorders collectively rank third among the world's most prevalent conditions and are the leading cause of disability in individuals under 50 years old — with migraine alone responsible for more years lived with disability than any other neurological condition. Headaches are classified by the International Headache Society into primary headaches — where headache is the disorder itself, with no underlying structural pathology — and secondary headaches, where headache is a symptom of an identifiable underlying cause. Primary headaches include tension-type headache (the most common, affecting up to 78% of the population), migraine (15% globally), and cluster headache (approximately 0.1%, predominantly in men). Secondary headaches arise from conditions ranging from the benign (medication overuse, caffeine withdrawal, dehydration, sinusitis) to the life-threatening (subarachnoid haemorrhage, bacterial meningitis, cerebral venous sinus thrombosis, hypertensive emergency, temporal arteritis, and intracranial mass). The critical clinical skill in headache assessment is identifying the minority of patients with secondary, potentially dangerous headaches from the large majority with primary headaches, and this is achieved through careful attention to the headache history and systematic red-flag screening.

Tension-type headache (TTH) is the most common primary headache: it presents as a dull, bilateral, pressure or tightening sensation described as a 'band around the head' or 'weight on the head', of mild to moderate intensity, not aggravated by routine physical activity, and without significant nausea or light/sound sensitivity. It is associated with pericranial muscle tenderness and is strongly linked to emotional stress, poor posture, sleep deprivation, and dehydration. Migraine is a neurovascular headache characterised by moderate to severe pulsating or throbbing pain, usually unilateral, lasting 4–72 hours, worsened by routine physical activity, accompanied by at least one of nausea or vomiting, and at least one of photophobia or phonophobia. Migraine with aura precedes the headache in approximately 30% of cases with reversible neurological symptoms — visual (scintillating scotoma, fortification spectra, or blurred vision), sensory (tingling spreading from one hand to the face), or speech disturbance — lasting 20–60 minutes. Cluster headache is a primary trigeminal autonomic cephalalgia producing severe, strictly unilateral, orbital or periorbital stabbing or burning pain lasting 15–180 minutes occurring in clusters of 1–8 attacks daily over weeks to months, accompanied by ipsilateral autonomic features (lacrimation, rhinorrhoea, ptosis, miosis, conjunctival injection). Secondary headache causes include: sinusitis (facial pressure and nasal symptoms); cervicogenic headache (from cervical spine disease); post-traumatic headache after concussion; hypertensive headache (particularly with systolic BP above 180 mmHg — hypertensive emergency); idiopathic intracranial hypertension (raised intracranial pressure from obesity or certain drugs, causing positional headache and pulsatile tinnitus); cerebral venous sinus thrombosis (CVST — particularly in women on OCPs); subarachnoid haemorrhage (SAH — thunderclap headache from ruptured aneurysm); bacterial meningitis (headache with fever, neck stiffness, photophobia); giant cell arteritis (GCA — new headache in over 50s with jaw claudication and temporal artery tenderness); and space-occupying lesions (tumour — progressive headache, worse lying or in the morning, with vomiting and neurological signs).

Recognising red-flag headache features is a critical clinical and patient safety skill. Call emergency services immediately for the sudden 'thunderclap' headache — a headache of maximum intensity reached within 60 seconds, described as the worst headache ever experienced — which is subarachnoid haemorrhage until proven otherwise by CT brain and lumbar puncture. This is one of medicine's most serious diagnoses, carrying 30% early mortality, and 12% of patients who die from SAH do so before reaching hospital. Seek emergency care for headache with fever and neck stiffness or inability to touch chin to sternum (bacterial meningitis — a treatable emergency where every hour of delayed antibiotic treatment worsens neurological outcome); headache with fever and a non-blanching rash (meningococcal disease); new severe headache in a person over 50 with scalp tenderness and jaw pain on chewing (giant cell arteritis — requires urgent same-day corticosteroid therapy to prevent blindness); headache with progressive neurological deficits — unilateral weakness, facial drooping, speech difficulty, or visual loss — lasting more than 1 hour (stroke or haemorrhagic lesion); headache following head injury even if initially mild (subdural haematoma can present days or weeks after trauma); headache with papilloedema (swollen optic discs indicating raised intracranial pressure) on fundoscopy; headache waking the patient consistently from sleep, worst in the morning, aggravated by coughing or lying flat, and accompanied by nausea or vomiting (raised ICP — possible intracranial mass); and first severe headache in a pregnant woman or postpartum woman (CVST or pre-eclampsia).

Comprehensive headache history is the cornerstone of diagnosis and is almost always sufficient to diagnose a primary headache disorder without neuroimaging. The clinician systematically establishes: onset (age at first attack; thunderclap onset versus gradual); location (unilateral versus bilateral, frontal versus occipital, behind the eye); character (pulsating, pressing, stabbing, band-like); severity (visual analogue scale 0–10; disability impact); duration of individual episodes; frequency and pattern (episodic versus daily); prodromes and aura (visual, sensory, speech symptoms preceding headache); trigger factors (stress, hormonal changes, specific foods — tyramine, caffeine, alcohol, artificial sweeteners — sleep changes, bright light, weather changes); associated symptoms (nausea, vomiting, photophobia, phonophobia, osmophobia, autonomic features); analgesic and triptan use frequency; impact on work, school, and social functioning; and family history of headache. General and neurological examination includes measurement of blood pressure, assessment of meningism (Kernig's sign, Brudzinski's sign, neck stiffness), fundoscopy for papilloedema, cranial nerve examination, and full neurological assessment of power, sensation, coordination, and reflexes. CT brain (without contrast, performed within 6 hours of thunderclap headache onset) detects subarachnoid haemorrhage in approximately 95% of cases within 6 hours. Lumbar puncture for xanthochromia (yellow discolouration of CSF from haemoglobin breakdown products) is performed when CT is negative but SAH is clinically suspected — it remains positive up to 12 days after the bleed. MRI brain with and without gadolinium is superior for detecting cerebral venous sinus thrombosis, intracranial mass, posterior fossa lesions, and intracranial hypertension. ESR and CRP are tested when giant cell arteritis is suspected (typically all above 50 are tested with new headache). Temporal artery ultrasound or biopsy confirms GCA.

Tension-type headache responds to simple analgesics — paracetamol (1000mg), ibuprofen (400mg), or aspirin (600mg) — taken at headache onset. Caffeine 65mg combined with analgesic enhances analgesic efficacy by approximately 40%. Non-pharmacological approaches are highly effective and should be first-line for frequent TTH: relaxation training, cognitive behavioural therapy addressing stress, physiotherapy for cervical muscle tenderness, and regular aerobic exercise. Tricyclic antidepressants (amitriptyline 10–75mg nightly) reduce chronic TTH frequency in preventive doses. Acute migraine attacks are most effectively treated when medications are taken at the earliest sign of headache onset. NSAIDs (naproxen 500mg, ibuprofen 400mg) combined with a prokinetic antiemetic (metoclopramide 10mg, domperidone 10mg) are effective first-line options. Triptans — selective serotonin 5-HT1B/1D receptor agonists (sumatriptan 50–100mg oral or 6mg subcutaneous injection; rizatriptan 10mg; eletriptan 40mg; zolmitriptan 2.5mg) — are the most specific and effective migraine treatments, achieving pain freedom in 2 hours in 50–70% of patients. Lasmiditan (a selective 5-HT1F agonist) and gepants (ubrogepant, rimegepant — oral CGRP receptor antagonists) are newer acute migraine treatments effective in triptan non-responders. Migraine prevention with daily medication is indicated when attacks occur 4 or more days per month, when attacks are severely disabling, or when acute treatments are ineffective: propranolol (40–240mg daily), amitriptyline (10–75mg nightly), topiramate (25–100mg daily), valproate, and CGRP monoclonal antibodies (erenumab, fremanezumab, galcanezumab — monthly subcutaneous injections producing 50% reduction in monthly migraine days in 50–60% of patients) are all evidence-based preventive options. Cluster headache acute attacks respond to high-flow oxygen (12–15 L/min via non-rebreather mask for 15–20 minutes) and subcutaneous sumatriptan (6mg); prevention during cluster periods uses verapamil (240–720mg daily) as first-line. Medication-overuse headache requires gradual withdrawal of the overused medication — best achieved with medical support as symptoms initially worsen before improvement.

Maintaining regularity is the most powerful migraine prevention lifestyle strategy — the migraine brain is highly sensitive to any disruption in homeostasis. Go to sleep and wake at the same time every day including weekends; avoid both sleep deprivation and oversleeping, as both trigger attacks. Eat regular meals at consistent times; never skip meals, as fasting and hypoglycaemia are potent migraine triggers. Stay well hydrated — aim for 8 glasses of water daily as dehydration commonly triggers headaches. Keep a detailed headache diary for at least 4–8 weeks to identify personal trigger patterns — common triggers include red wine and other alcoholic drinks; aged cheeses, cured and processed meats (tyramine); chocolate; artificial sweeteners (aspartame); caffeine — either as a trigger when consumed or as a withdrawal headache if suddenly stopped; monosodium glutamate (MSG); hormonal fluctuations in women (perimenstrual migraine responds to oestrogen supplementation or frovatriptan taken peri-menstrually); bright, flickering, or fluorescent light; loud noise; strong smells; weather changes (barometric pressure changes); and high altitude. Limit analgesic use strictly to fewer than 10–15 days per month for any headache medication — medication overuse is one of the most common causes of chronic daily headache and perpetuates a cycle of worsening headache that breaks only with analgesic withdrawal. Practice stress management through regular aerobic exercise (3–5 sessions per week reduces migraine frequency), mindfulness-based stress reduction, yoga, and adequate social support. Reduce alcohol, particularly red wine, dark beer, and spirits, all of which are consistent migraine triggers. Wear polarised sunglasses in bright light and use blue-light filtering screens for photosensitivity.

Call emergency services immediately for the sudden thunderclap headache — the worst headache of your life peaking within 60 seconds — as this is subarachnoid haemorrhage until proven otherwise and requires emergency CT brain and potentially lumbar puncture within hours. Call emergency services for headache with fever and neck stiffness (cannot touch chin to chest), headache with a petechial or purpuric non-blanching rash, headache with neurological deficits (arm or leg weakness, facial drooping, speech difficulty, visual loss) persisting more than 1 hour, or headache with confusion or altered consciousness — all of which represent neurological or vascular emergencies. Seek urgent same-day emergency assessment for new severe headache in a person over 50 years old with temporal artery tenderness or jaw pain — possible giant cell arteritis requiring same-day corticosteroids to prevent irreversible blindness. Schedule a priority GP appointment within 1–2 weeks for any of the following: headaches occurring more than 15 days per month (chronic daily headache); headaches progressively worsening in frequency or severity over weeks; headaches consistently awakening you from sleep; a first migraine (to confirm diagnosis and access preventive treatment); headaches not responding to over-the-counter analgesics; or suspected medication overuse headache. Routine appointment for established migraine or tension-type headache that has changed in character or is less well controlled than usual. Children with frequent headaches, particularly with morning nausea or vomiting and visual disturbances, require paediatric neurological assessment to exclude raised intracranial pressure.