Migraine vs. Other Headaches: How to Tell the Difference

38% of the Population Has a Headache Disorder — But Not the Same One

Headache disorders affect approximately 3 billion people worldwide, making them the third most prevalent medical condition on the planet. Tension-type headache alone affects 38% of the global population at some point in their lives. Migraine affects approximately 12% of Americans — about 39 million people — and is the second leading cause of disability globally among all diseases. Despite their prevalence, headache disorders are consistently underdiagnosed, misclassified, and undertreated: a 2018 survey found that fewer than 50% of migraine sufferers had received a formal diagnosis from a physician, and many were self-treating with over-the-counter analgesics in patterns that paradoxically worsen their condition.

The International Classification of Headache Disorders, 3rd edition (ICHD-3), published by the International Headache Society in 2018, provides the definitive diagnostic framework — organizing headache into primary headaches (the condition itself is the disease), secondary headaches (caused by an underlying condition), and painful cranial neuropathies. Understanding these distinctions is clinically essential: the treatment for tension-type headache will worsen a cluster headache, and the "worst headache of my life" that mimics a migraine may be a subarachnoid hemorrhage requiring immediate CT and lumbar puncture.

Migraine: A Four-Phase Neurological Disease

Migraine is not simply a bad headache — it is a neurological disorder with four distinct phases that many sufferers experience predictably. The pathophysiology involves trigeminovascular activation, cortical spreading depression (CSD), and neuroinflammation. CSD — a slowly propagating wave of neuronal and glial depolarization followed by sustained suppression — is the mechanism underlying the aura in migraine with aura.

• Prodrome (hours to days before pain): Mood changes (irritability or euphoria), food cravings, yawning, neck stiffness, cognitive fog, and increased urination. Occurs in 60–80% of migraineurs. Recognition of prodrome can allow preemptive treatment.
• Aura (20–60 minutes before or during headache): Fully reversible neurological symptoms lasting 5–60 minutes. Visual auras are most common — scintillating scotomas, fortification spectra (zigzag lines), or hemianopic visual loss. Sensory (hemisensory tingling spreading over minutes) and speech/language auras also occur. Occurs in approximately 25–30% of migraineurs.
• Headache phase (4–72 hours): Unilateral, pulsating pain of moderate-to-severe intensity, worsened by routine physical activity, associated with nausea/vomiting and photophobia/phonophobia. At least two of the first three pain characteristics plus at least one associated symptom are required for ICHD-3 diagnosis.
• Postdrome (hours after pain resolves): "Migraine hangover" — fatigue, cognitive slowing, mood changes, and persistent nausea. Often more disabling than the headache phase itself in terms of lost productivity.

ICHD-3 Diagnostic Criteria for Migraine Without Aura

The ICHD-3 criteria require at least 5 attacks fulfilling the following criteria:

• Headache lasting 4–72 hours (untreated or unsuccessfully treated)
• At least two of: unilateral location, pulsating quality, moderate-severe intensity, aggravation by routine physical activity
• At least one of: nausea/vomiting OR photophobia AND phonophobia
• Not better accounted for by another ICHD-3 diagnosis

The criteria for chronic migraine require headache on 15 or more days per month for more than 3 months, with migraine features on at least 8 of those days. Chronic migraine affects approximately 2–3% of the global population and represents one of the most disabling neurological conditions in working-age adults.

Headache Type Comparison

Cluster Headache: The Suicide Headache

Cluster headache is the most severe primary headache disorder — often described by patients as the worst pain a human can experience, earning the informal designation "suicide headache." It affects approximately 0.1% of the population, with a 3:1 male predominance. Attacks occur in clusters lasting weeks to months, with 1–8 attacks per day, each lasting 15–180 minutes. During an attack, the ipsilateral autonomic features (tearing, red eye, nasal congestion or rhinorrhea, ptosis, facial sweating) are pathognomonic — distinguishing it from migraine even when pain is frontal.

The restlessness of cluster headache — patients pace, rock, or bang their heads rather than lying still as migraineurs prefer — is a clinical pearl. Treatment requires two components: abortive therapy (high-flow oxygen at 12–15 L/min via non-rebreather mask, achieving relief in 66–78% of attacks; subcutaneous sumatriptan) and preventive therapy during the cluster period (verapamil 240–960 mg/day; short-course prednisone; lithium for chronic cluster). Galcanezumab (CGRP monoclonal antibody) received FDA approval for episodic cluster headache prevention in 2019.

Medication Overuse Headache: The Paradoxical Trap

Medication overuse headache (MOH) — formerly called "rebound headache" — is defined by the ICHD-3 as headache occurring on 15 or more days per month in a patient with a pre-existing primary headache disorder, developing as a consequence of regular overuse of acute headache medication for more than 3 months. The threshold for overuse is:

• 10 or more days per month for ergotamines, triptans, opioids, or combination analgesics
• 15 or more days per month for simple analgesics (acetaminophen, NSAIDs)

MOH affects approximately 1% of the general population and up to 50% of patients at headache specialty clinics. The perverse biology: chronic analgesic use downregulates endogenous pain modulation systems, lowering the threshold at which headache occurs, creating a cycle where each dose of the medication that temporarily relieves pain also primes the nervous system for the next headache. Treatment requires withdrawal of the overused medication — a process that temporarily worsens headache before improvement — combined with preventive therapy. Opioids and butalbital-containing analgesics carry the highest MOH risk.

Red Flag Headaches: When to Image Immediately

The following features require urgent neuroimaging (CT without contrast for emergent scenarios, MRI with/without contrast for subacute workup) and, in some cases, lumbar puncture:

• Thunderclap headache: Severe headache reaching maximum intensity in under 60 seconds — subarachnoid hemorrhage until proven otherwise
• First or worst headache of life: Even if characteristics suggest migraine, first severe headache requires exclusion of hemorrhage
• Headache with fever and neck stiffness: Meningitis or encephalitis
• Headache with new focal neurological deficit: Stroke, mass, or abscess
• Headache in cancer or HIV patients: Metastasis, cryptococcal meningitis, toxoplasmosis
• Postural headache (worse when upright): Intracranial hypotension (CSF leak)
• Progressive headache worsening over weeks: Mass lesion

CGRP: From Biomarker to Treatment Target

Calcitonin gene-related peptide (CGRP) is a neuropeptide released from trigeminal nerve terminals during migraine attacks, causing vasodilation, neurogenic inflammation, and central sensitization. Elevated CGRP levels are measurable in jugular venous blood during migraine attacks and normalize with effective triptan treatment — establishing CGRP as the first validated biomarker of migraine biology.

This discovery launched the most significant advance in migraine prevention in decades: monoclonal antibodies targeting CGRP (eptinezumab/Vyepti, fremanezumab/Ajovy, galcanezumab/Emgality) or the CGRP receptor (erenumab/Aimovig) are the first migraine-specific preventive medications, administered monthly or quarterly by injection. Clinical trials show approximately 50% of patients achieve a 50% or greater reduction in monthly migraine days — substantially better than traditional preventives (topiramate, propranolol, amitriptyline) and with fewer systemic side effects. Small molecule CGRP receptor antagonists (gepants: ubrogepant/Ubrelvy, rimegepant/Nurtec) provide acute and preventive treatment in pill form. CGRP-targeted therapy has fundamentally changed the migraine treatment landscape in the six years since the first approval in 2018.