Headache: When to See a Doctor, Causes, and Treatment

When Should You Worry About a Headache?

Most headaches are benign. A very small percentage are caused by life-threatening pathology, and distinguishing between them is the central clinical task. The mnemonic SNOOP4 (Systemic symptoms, Neurological signs, Onset sudden, Onset after age 50, Pattern change, Postural aggravation, Papilledema, Precipitated by Valsalva) captures the red flags used by neurologists to identify headaches that require urgent imaging or emergency evaluation. The American Headache Society and the American Academy of Neurology endorse SNOOP as a structured red-flag screening tool in clinical practice.

The Thunderclap Headache

A thunderclap headache reaches maximum intensity within 60 seconds. Call 911 immediately. Subarachnoid hemorrhage (SAH) from a ruptured aneurysm presents this way in roughly 80% of cases, and 30-day case fatality for SAH remains near 45% even with modern neurosurgical care. Non-traumatic subarachnoid hemorrhage accounts for approximately 5% of all stroke presentations, but missing it is catastrophic. Non-contrast CT detects SAH with sensitivity exceeding 98% within 6 hours of onset; sensitivity drops to roughly 85-90% after 24 hours, at which point lumbar puncture is required to exclude xanthochromia.

Neurological Red Flags

Headache accompanied by any of the following demands same-day evaluation, not a next-available appointment.

• Focal weakness, unilateral numbness, or speech difficulty
• Diplopia or acute vision change
• Altered consciousness or confusion
• Fever above 38.3°C combined with neck stiffness and photophobia (classic triad of bacterial meningitis)
• Headache in a patient with known HIV, active cancer, or immunosuppressive therapy
• New headache in a patient older than 50 years (raises suspicion for giant cell arteritis or intracranial mass)

The British Association for the Study of Headache (BASH) guidelines specify that new-onset severe headache in patients over 50 should prompt ESR and CRP testing within 24 hours to rule out giant cell arteritis, which carries a risk of permanent vision loss if untreated.

Headache After Head Trauma

Post-traumatic headache beginning within 7 days of a head injury, or worsening after an initial improvement, requires CT imaging to exclude subdural hematoma. The CDC Pediatric mTBI Guideline provides age-specific decision tools for managing post-concussive headache in children, though the same principles of clinical vigilance apply in adults.

What Causes Headaches?

Headache disorders are classified by the International Classification of Headache Disorders, 3rd edition (ICHD-3), which divides them into primary (no underlying structural cause) and secondary (caused by another condition). The ICHD-3 classification is published by the International Headache Society and remains the global diagnostic standard.

Tension-Type Headache

Tension-type headache (TTH) is the most common primary headache. It produces bilateral, pressing or tightening pain of mild-to-moderate intensity, not aggravated by routine physical activity, without nausea, and with at most one of photophobia or phonophobia. A large population-based study estimated lifetime prevalence of TTH at 78% in the general adult population.

Triggers include sleep deprivation, psychological stress, poor posture, dehydration, and skipped meals. Episodic TTH (fewer than 15 headache days per month) responds well to ibuprofen 400 mg or acetaminophen 1,000 mg taken early. Chronic TTH (15 or more days per month for over 3 months) requires preventive pharmacotherapy; amitriptyline 10-75 mg nightly is the most evidence-supported agent for this form.

Migraine

Migraine is a neurovascular disorder characterized by recurrent attacks of moderate-to-severe unilateral pulsating headache lasting 4-72 hours, often accompanied by nausea or vomiting, and aggravation by routine activity. Roughly one-third of migraineurs experience aura: transient, fully reversible neurological symptoms (visual, sensory, or speech) that typically precede headache by 20-60 minutes.

The Global Burden of Disease 2016 Study ranked migraine as the second leading cause of disability worldwide, with an estimated 1.04 billion people affected globally.

Triptans (5-HT1B/1D agonists) are first-line prescription therapy for moderate-to-severe migraine. Sumatriptan 100 mg orally produces 2-hour pain freedom in approximately 37% of patients versus 11% for placebo in randomized controlled trials. A Cochrane systematic review of sumatriptan (N=12,339 participants across 47 trials) confirmed that sumatriptan 100 mg oral achieved 2-hour headache relief in 57% of attacks. For patients who cannot tolerate oral dosing during an attack, sumatriptan 6 mg subcutaneous injection is available.

Newer gepant-class medications (ubrogepant, rimegepant) and lasmiditan (a 5-HT1F agonist) offer alternatives for patients with cardiovascular contraindications to triptans. The FDA approved rimegepant (Nurtec ODT) in 2020 for both acute and preventive migraine treatment, making it one of the few agents approved for both indications.

Cluster Headache

Cluster headache is the most severe primary headache syndrome. Pain is strictly unilateral, periorbital or temporal, excruciating in intensity, and lasts 15-180 minutes. Attacks occur in clusters (typically 6-12 weeks) one to eight times daily, often at night. Autonomic features on the ipsilateral side (ptosis, miosis, lacrimation, nasal congestion) differentiate it from migraine. Prevalence is approximately 0.1% of the population, with a male-to-female ratio of approximately 3:1.

Acute treatment: high-flow 100% oxygen at 12-15 L/min via non-rebreather mask for 15-20 minutes aborts attacks in 60-70% of patients. Subcutaneous sumatriptan 6 mg is equally effective and acts faster. Verapamil 240-960 mg daily is the standard preventive agent during cluster periods.

Secondary Headaches: Key Causes

Secondary headaches have an identifiable underlying cause. Common and clinically significant examples include:

• Medication overuse headache (MOH): Using acute headache medications on 10 or more days per month for over 3 months paradoxically increases headache frequency. The prevalence of MOH is approximately 1-2% of the general population and represents up to 50% of patients attending specialist headache clinics. Withdrawal of the overused medication is the definitive treatment, though patients typically experience a worsening "washout" headache for 2-10 days.
• Intracranial hypertension: Idiopathic intracranial hypertension (IIH) causes daily headache, pulsatile tinnitus, and transient visual obscurations, predominantly in women with obesity. A retrospective cohort study found that weight loss of 6% body weight reduces CSF opening pressure significantly in IIH.
• Cervicogenic headache: Referred pain from the upper cervical spine, occipital nerve distribution, unilateral, aggravated by neck movement.
• Giant cell arteritis (GCA): New temporal headache in patients over 50, with scalp tenderness, jaw claudication, and elevated ESR (often above 50 mm/hr). GCA is a medical urgency; oral prednisolone 40-60 mg daily should start before biopsy results return to prevent vision loss.

How Is a Headache Diagnosed?

Diagnosis is primarily clinical. No blood test or scan diagnoses migraine or tension-type headache directly; those diagnoses rest on history and examination. Imaging is indicated for red-flag features, not for routine primary headache presentations.

History Taking

A structured headache history captures: onset (sudden vs. Gradual), location, quality, severity (0-10 scale), duration, frequency, associated symptoms, triggers, aggravating and relieving factors, medication use, and family history. The PQRST mnemonic (Provocation, Quality, Radiation, Severity, Timing) provides a useful framework.

Headache diaries completed over 4-8 weeks give more reliable frequency and trigger data than patient recall. The American Migraine Foundation recommends dedicated headache diary apps or paper logs as standard practice before initiating preventive therapy.

Physical and Neurological Examination

Assess blood pressure (hypertensive emergency can cause headache at systolic pressures above 180 mmHg), fundoscopy for papilledema, cranial nerve function, motor and sensory symmetry, coordination, and meningeal signs (Kernig and Brudzinski). A normal neurological examination in a patient with a chronic stable headache pattern is strongly reassuring.

Imaging

The American College of Radiology (ACR) Appropriateness Criteria for headache specify that CT without contrast is the most appropriate initial study for acute severe headache in the emergency setting. MRI with and without gadolinium is preferred for sub-acute or chronic headache with red flags, suspected venous thrombosis, or posterior fossa pathology, because MRI has superior sensitivity for those conditions.

Routine imaging of patients with a long-standing, unchanged primary headache pattern and a normal neurological examination is not recommended by current guidelines, as yield is extremely low and incidental findings create unnecessary anxiety and downstream testing.

Blood Tests

Order CBC, ESR, CRP, and temporal artery ultrasound when GCA is suspected. Thyroid function tests identify hypothyroid-associated headache. Serum glucose excludes hypoglycemia. Lumbar puncture is indicated when CT is negative but SAH or meningitis remains clinically suspected, and should measure opening pressure, cell count, protein, glucose, and xanthochromia.

Treatment for Headache

Treatment divides into acute (abortive) therapy and preventive therapy. The choice depends on headache type, frequency, severity, and the presence of contraindications.

Acute Treatment Options

Tension-type headache:

• Ibuprofen 400-600 mg (NNT approximately 5 for 50% pain relief)
• Acetaminophen 1,000 mg (NNT approximately 12)
• Aspirin 1,000 mg (comparable efficacy to ibuprofen in direct comparison trials)
• Caffeine 65-130 mg added to analgesics improves efficacy by approximately 40% in episodic TTH

A Cochrane review of ibuprofen for acute TTH (N=3,180) found that ibuprofen 400 mg produced at least 50% pain relief in 48% of participants vs. 27% for placebo.

Migraine:

• Mild attacks: NSAIDs or acetaminophen plus an antiemetic (metoclopramide 10 mg or prochlorperazine 10 mg)
• Moderate-to-severe attacks: triptan (sumatriptan, rizatriptan, eletriptan, zolmitriptan), taken as early as possible during the headache phase
• Refractory attacks: IV valproate 400-800 mg, IV prochlorperazine 10 mg, or IV ketorolac 30 mg in emergency settings
• Gepants (ubrogepant 50-100 mg, rimegepant 75 mg) for patients with cardiovascular risk or triptan failure

Cluster headache: 100% oxygen 12-15 L/min for up to 20 minutes, or subcutaneous sumatriptan 6 mg.

Preventive Therapy

Preventive therapy is indicated when headaches occur on 4 or more days per month, when acute medications are overused, when attacks are severely disabling despite adequate acute therapy, or when acute medications are contraindicated.

Evidence-based preventive options for migraine:

| Agent | Daily Dose | Level of Evidence | |---|---|---| | Topiramate | 50-200 mg | Level A (AAN guideline) | | Valproate/divalproex | 500-1,500 mg | Level A | | Propranolol | 80-240 mg | Level A | | Amitriptyline | 10-75 mg | Level B | | Candesartan | 16 mg | Level B | | Erenumab (CGRP mAb) | 70 or 140 mg SC monthly | FDA-approved 2018 | | Fremanezumab | 225 mg SC monthly | FDA-approved 2018 | | Galcanezumab | 120 mg SC monthly | FDA-approved 2018 |

The anti-CGRP monoclonal antibodies (erenumab, fremanezumab, galcanezumab, eptinezumab) represent the first preventive drug class developed specifically for migraine. In the STRIVE trial (N=955), galcanezumab 120 mg reduced monthly migraine days by 4.7 days versus 2.8 days for placebo (P<0.001).

A 2021 American Academy of Neurology practice guideline update states: "Clinicians should offer topiramate (Level A), valproate (Level A), metoprolol (Level A), propranolol (Level A), or timolol (Level A) to patients with episodic migraine who require preventive treatment."

The HealthRX Headache Triage Framework below summarizes when to act, wait, or refer, based on the red-flag criteria and headache frequency thresholds covered in this article.

| Clinical Scenario | Action | |---|---| | Thunderclap headache (peak intensity <60 seconds) | Call 911. Do not drive. | | Headache with fever, neck stiffness, rash | Emergency department immediately | | New neurological symptoms with headache | Same-day emergency evaluation | | New headache in patient over 50 | Same-day GP visit; ESR/CRP within 24 hours | | Headache worsening over weeks in a known cancer patient | Urgent MRI referral within 48 hours | | Stable primary headache, 1-3 days/month, no red flags | OTC analgesia; GP review if no improvement in 2 weeks | | Headache 4+ days/month, affecting function | GP visit; consider preventive therapy | | Acute medication use 10+ days/month | GP or neurologist referral for MOH management |

Non-Pharmacological Approaches

Behavioral and physical interventions have Level A or B evidence for migraine prevention. A meta-analysis of cognitive behavioral therapy (CBT) for chronic headache (k=25 trials, N=2,463) found a standardized mean difference of -0.56 for headache frequency, comparable to pharmacotherapy in that analysis.

Evidence-supported non-drug options include:

• Biofeedback (electromyographic or thermal): reduces migraine frequency by 45% on average across controlled trials
• CBT targeting stress appraisal and sleep hygiene
• Aerobic exercise 3 times weekly, 40 minutes per session: comparable to topiramate in a 3-arm RCT for migraine prevention
• Acupuncture: 10 sessions over 5-8 weeks produces modest but statistically significant reductions in headache days versus sham acupuncture

Medication Overuse Headache: A Practical Note

Patients using any acute headache medication, whether triptans, NSAIDs, or combination analgesics containing caffeine or opioids, on 10-15 or more days per month for more than 3 months should be counseled on MOH. European Headache Federation guidelines recommend abrupt or gradual withdrawal of the overused medication as the primary intervention, with close follow-up during the 2-10 day withdrawal period.

Patients overusing opioids or butalbital-containing compounds may require supervised inpatient or outpatient detoxification. Those overusing simple analgesics or triptans can usually withdraw as outpatients with education and short-term bridging therapy (e.g., naproxen 500 mg twice daily for 10-14 days).

Headaches in Special Populations

Headache in Pregnancy

Migraine affects 18% of women of reproductive age, and attack frequency changes during pregnancy, often improving in the second and third trimesters as estrogen levels stabilize. Triptans are not FDA-approved in pregnancy; available registry data are generally reassuring but insufficient to rule out risk definitively. Acetaminophen is the preferred acute agent. For prevention, magnesium glycinate 400-600 mg daily has the most favorable safety profile. The American Migraine Foundation recommends magnesium supplementation as a first-line preventive option during pregnancy.

New-onset severe headache in the third trimester or postpartum requires blood pressure measurement to exclude preeclampsia/eclampsia, which can present with headache as the sole initial symptom.

Headache in Children and Adolescents

Migraine occurs in approximately 7.7% of children aged 5-15 years. A systematic review of pediatric migraine prevalence found rates rising from 3% before age 7 to nearly 10% in adolescents. Ibuprofen 7.5-10 mg/kg (max 400 mg) is the best-supported acute treatment in children. Sumatriptan nasal spray 10-20 mg is FDA-approved for adolescents aged 12 and older. Amitriptyline, topiramate, and propranolol are used for pediatric prevention, though large RCT data in children are more limited than in adults.