Emergency red flags — the "SNOOP4" criteria
Thunderclap onset — reaches maximum severity within 60 seconds ("worst headache of my life") · Headache with fever and stiff neck (possible meningitis) · Headache with confusion, seizure, or focal weakness · Headache after head trauma · New headache in someone over 50 (possible temporal arteritis or malignancy) · Headache that wakes you from sleep · Headache with vision loss or jaw claudication · New headache in someone with cancer or HIV · Headache with scalp tenderness in older adults
Tension-type headache
The most common type — affecting up to 78% of the general population at some point. Tension headaches produce a pressing or tightening, non-pulsating bilateral headache — often described as a tight band or vice around the head. Mild to moderate intensity. Not worsened by routine physical activity. No nausea or vomiting. Mild light or sound sensitivity may be present (but not both simultaneously — which would suggest migraine).
Duration ranges from 30 minutes to 7 days. Episodic tension headache (<15 days/month) is managed with simple analgesics (paracetamol, NSAIDs) and addressing triggers. Chronic tension headache (≥15 days/month) may require preventive therapy and cognitive-behavioural approaches.
One of the most important — and most misunderstood — headache diagnoses. Regular use of acute headache medications more than 10–15 days per month (depending on the class) paradoxically causes chronic daily headache. Triptans and opioids carry the highest risk. Treatment requires withdrawing the overused medication — which initially worsens headache before improvement. If you are taking headache medication more than 2–3 times per week, discuss this with your doctor.
Migraine: a neurological disease, not "just a headache"
Migraine is the third most prevalent illness globally and the leading cause of disability in under-50s. It affects approximately 1 billion people worldwide — and is significantly underdiagnosed and undertreated. It is a neurological disease involving dysregulation of the trigeminovascular system and cortical spreading depression.
The four phases of migraine
| Phase | Timing | Features |
|---|---|---|
| 1. Prodrome | Hours to days before headache | Mood changes, food cravings, yawning, neck stiffness, fatigue — occurs in 60% of migraineurs |
| 2. Aura | 5–60 minutes before or during headache | Visual (zigzag lines, blind spots — most common), sensory (tingling), or speech disturbance; occurs in ~25% of migraineurs |
| 3. Headache | 4–72 hours | Moderate-to-severe unilateral pulsating pain; nausea/vomiting; photophobia; phonophobia; worsened by routine activity |
| 4. Postdrome | Hours after headache | "Migraine hangover" — fatigue, cognitive difficulty, mood changes; experienced by 80% of migraineurs |
CGRP — the science behind new migraine drugs
Calcitonin gene-related peptide (CGRP) is a neuropeptide central to migraine pathophysiology — released during attacks and elevated interictally in chronic migraine. CGRP-targeting drugs represent the first treatments specifically developed for migraine rather than repurposed from other conditions.
| Drug (class) | Route | For | Key benefit |
|---|---|---|---|
| Erenumab (Aimovig) | Monthly SC | Prevention | Anti-CGRP receptor antibody; 50% reduction in monthly migraine days in ~50% of patients |
| Fremanezumab (Ajovy) | Monthly or quarterly SC | Prevention | Anti-CGRP antibody; quarterly dosing option improves adherence |
| Galcanezumab (Emgality) | Monthly SC | Prevention + cluster | Only CGRP mAb approved for cluster headache prevention |
| Ubrogepant (Ubrelvy) | Oral tablet | Acute treatment | CGRP receptor antagonist (gepant); effective even if taken during established migraine |
| Rimegepant (Nurtec) | Oral dissolving tablet | Acute + prevention | Only drug approved for both acute treatment AND prevention (every other day) |
| Lasmiditan (Reyvow) | Oral tablet | Acute treatment | Serotonin 5-HT1F agonist (ditan); no vasoconstriction — safe in cardiovascular disease |
Migraine prevention — older options
- Beta-blockers (propranolol, metoprolol): First-line prevention; reduce attack frequency by ~50% in responders
- Topiramate: Anticonvulsant with strong evidence; weight loss side effect can be beneficial or problematic; avoid in pregnancy (teratogenic)
- Amitriptyline: Tricyclic antidepressant; particularly useful when comorbid depression or insomnia; sedating
- Valproate: Effective but teratogenic — avoid in women of childbearing potential
- OnabotulinumtoxinA (Botox): 31 injections around the head and neck every 12 weeks — approved for chronic migraine (≥15 headache days/month)
- Candesartan: ARB with good evidence; particularly useful in those with hypertension comorbidity
Cluster headache
The most painful headache disorder — described by patients as a "hot poker behind the eye" or "suicide headache." Strictly unilateral, centred around or behind one eye, of excruciating severity (9–10/10), brief duration (15–180 minutes), occurring in clusters of weeks to months followed by remission periods. The ipsilateral autonomic features are pathognomonic: tearing, red eye, nasal congestion, eyelid drooping, and forehead sweating on the same side as the pain.
Unlike migraine, patients are restless and agitated during an attack — pacing, rocking. Attacks often occur at the same time of day, frequently waking patients from sleep. Triggers during a cluster period include alcohol and strong smells.
- Acute treatment: High-flow 100% oxygen (12–15 L/min for 15 minutes) — highly effective; subcutaneous sumatriptan — fastest onset triptan; intranasal zolmitriptan
- Preventive: Verapamil is first-line; galcanezumab (Emgality) — first CGRP antibody approved for episodic cluster; lithium for chronic cluster; short-course corticosteroids to break a cluster
Dangerous secondary headaches
| Condition | Key features | Urgency |
|---|---|---|
| Subarachnoid haemorrhage (SAH) | Thunderclap onset; worst headache of life; may have brief loss of consciousness; neck stiffness develops | 911 now |
| Bacterial meningitis | Fever + headache + neck stiffness (triad); photophobia; non-blanching rash in meningococcal disease | 911 now |
| Brain tumour | Progressive headache worse in morning or with Valsalva; personality change; focal neurological signs | Urgent neurology |
| Temporal arteritis (GCA) | Age >50; new temporal headache; scalp tenderness; jaw claudication; risk of blindness if untreated | Same-day assessment |
| Cerebral venous thrombosis | Progressive headache; often in young women on OCP, puerperium, or hypercoagulable state; can cause seizures | ER urgently |
| Idiopathic intracranial hypertension | Obese women; pulsatile tinnitus; visual obscurations; papilloedema on fundoscopy | Urgent ophthalmology/neurology |
Diagnosis approach
The vast majority of headache diagnoses are clinical — made on history and examination without the need for imaging. Neuroimaging (CT or MRI) is indicated for: new or changed headache pattern; headache with red flag features; headache unresponsive to appropriate treatment; or clinical uncertainty.
A headache diary is invaluable — recording onset, duration, location, severity, associated symptoms, triggers, medication taken, and response. Most smartphone apps provide suitable formats. A 4–8 week diary significantly improves diagnostic precision and treatment monitoring.
Treatment: acute and preventive
Tension headache: Paracetamol 1g or ibuprofen 400 mg — most effective when taken early. Aspirin 900 mg is equally effective. Avoid opioids — addiction risk and MOH.
Migraine: Triptans (sumatriptan, rizatriptan, eletriptan) remain first-line for moderate-severe attacks in most patients — most effective when taken early. NSAIDs ± antiemetics (domperidone, metoclopramide) for mild attacks. New gepants (ubrogepant, rimegepant) for those with cardiovascular contraindications to triptans or triptan non-responders. Lasmiditan for cardiovascular disease patients.
Important: Do not use acute headache treatments more than 10 days/month (triptans, ergotamines) or 15 days/month (simple analgesics) — medication overuse headache risk.
Prevention is indicated when migraines occur ≥4 days/month, are severely disabling, or acute treatments are contraindicated or fail. Target: ≥50% reduction in monthly migraine days.
Options by evidence strength: CGRP monoclonal antibodies (erenumab, fremanezumab, galcanezumab) — best tolerated with strongest evidence; beta-blockers (propranolol, metoprolol); topiramate; amitriptyline; candesartan; Botox (chronic migraine). Choose based on comorbidities, contraindications, and patient preference.
Consistent daily routines dramatically reduce migraine frequency for many patients:
- Sleep: Regular wake and sleep times — even on weekends. Both sleep deprivation and oversleeping trigger migraines.
- Hydration: Dehydration is a potent trigger — aim 2–3 litres of water daily.
- Meal regularity: Skipping meals and fasting trigger migraines. Eat at consistent times.
- Caffeine: Regular caffeine use and caffeine withdrawal both trigger headaches. If caffeine-dependent, wean gradually.
- Stress management: Stress is the most commonly reported migraine trigger. Mindfulness-Based Stress Reduction (MBSR) has RCT evidence for migraine reduction.
- Exercise: Regular aerobic exercise reduces migraine frequency — but intense sudden exercise can trigger attacks. Build gradually.
- Screen time: Blue light and screen glare worsen migraines. Use blue-light filters and take regular breaks.
Frequently asked questions
A thunderclap headache is a sudden, extremely severe headache that reaches its maximum intensity within 60 seconds — often described as the worst headache of your life. It is a medical emergency requiring immediate evaluation to exclude subarachnoid haemorrhage (bleeding around the brain from a ruptured aneurysm), which is fatal or severely disabling in around 30–40% of cases. Call 911 immediately. Even if investigations are negative, a thunderclap headache requires thorough evaluation.
Migraine is typically a moderate-to-severe, pulsating, one-sided headache lasting 4–72 hours, accompanied by nausea and/or vomiting, and sensitivity to light and sound. Physical activity worsens the pain — making you want to lie down in a dark, quiet room. About 25% of migraines are preceded by an aura. If you have recurring headaches that fit this description, speak to your GP — migraine is significantly undertreated, and effective therapies exist.
Go to the ER immediately for: sudden thunderclap headache; headache with fever and stiff neck; headache with confusion, seizure, or focal weakness; headache after head injury; new headache in someone with cancer or HIV; a headache you would describe as the worst of your life; or any headache pattern that is completely different from your usual headaches. When in doubt, always err on the side of getting assessed.
- Headache Classification Committee of the International Headache Society. The International Classification of Headache Disorders, 3rd edition. Cephalalgia. 2018;38(1):1–211.
- Goadsby PJ, et al. Pathophysiology of migraine. NEJM. 2017;377(6):553–561.
- Tepper SJ. Anti–Calcitonin Gene-Related Peptide (CGRP) Therapies. Headache. 2018;58(Suppl 3):238–258.
- Diener HC, et al. OnabotulinumtoxinA for treatment of chronic migraine (PREEMPT). Cephalalgia. 2010;30(7):804–814.
- Olesen J. Headache Classification Committee of the International Headache Society. Lancet Neurol. 2018;17(2):162–172.