What Is a Migraine? Symptoms, Causes and Types Explained

Migraine is one of the most common neurological conditions in the world, yet it remains widely misunderstood and underdiagnosed. If you experience recurring, disabling headaches — often with nausea, light sensitivity, or visual changes — migraine may be the underlying diagnosis. This article explains what migraine is, how attacks unfold, what causes them, the key differences between migraine types, and the real-world burden the condition places on people's lives.

What is a migraine?

Migraine is a genetically influenced neurological disorder characterised by recurrent attacks of moderate-to-severe headache, typically one-sided and pulsating, with associated symptoms that can be as disabling as the pain itself (Pescador Ruschel & De Jesus, StatPearls, 2024). It is not simply a severe headache — it is a distinct neurological condition with its own diagnostic criteria.

Migraine directly affects more than 1 billion people worldwide, making it one of the most prevalent neurological disorders on the planet (Eigenbrodt et al., Nature Reviews Neurology, 2021). In the UK alone, migraine affects approximately 10 million people — 1 in 7 adults — and accounts for 1 in 10 GP consultations (Hind et al., BJGP Open, 2025). Despite this scale, the condition remains significantly under-diagnosed and under-treated in both primary and secondary care (Eigenbrodt et al., 2021).

Migraine is classified by the International Headache Society as a primary headache disorder — meaning the migraine itself is the diagnosis, not a symptom of something else (ICHD-3). It is the second leading cause of years lived with disability globally and the leading cause in women under 50 (WHO, Global Burden of Disease). For more on this distinction, see our guide to primary vs secondary headaches.

The four phases of a migraine attack

Migraine attacks typically unfold in four phases, though not everyone experiences all four at every attack — or at all.

1. Prodrome (hours to days before): Subtle changes that signal an attack is coming. These may include mood shifts, fatigue, food cravings, increased yawning, neck stiffness, or sensitivity to light. Recognising prodrome symptoms early can help you prepare or act on any agreed management plan.
2. Aura (20–60 minutes, usually before the headache): Temporary neurological symptoms that develop gradually. Aura occurs in roughly 25–30% of people with migraine (ICHD-3). Not every attack with aura involves one, and aura can sometimes occur without a following headache.
3. Headache phase (4–72 hours): The main attack. Moderate-to-severe pain, usually one-sided, that worsens with movement. Nausea, vomiting, and sensitivity to light and sound are common. This is the phase most people associate with the word "migraine."
4. Postdrome (up to 48 hours after): Sometimes called the "migraine hangover." Fatigue, difficulty concentrating, mood changes, and residual head sensitivity are common, even after the pain has resolved.

What is migraine aura?

Aura refers to a set of fully reversible neurological symptoms that develop gradually over 5–20 minutes and typically resolve within 60 minutes (ICHD-3). Aura most commonly affects vision, but can also involve sensory and speech changes.

Types of aura include:

• Visual aura (most common): Zigzag lines (fortification spectra), flickering or shimmering lights, blind spots (scotomas), or blurred vision. These appear in the visual field of both eyes, not just one eye.
• Sensory aura: Pins and needles or numbness that spreads gradually, typically from the hand up the arm or across the face.
• Speech or language aura (dysphasia): Difficulty finding words or speaking clearly. Less common than visual or sensory aura.
• Motor aura: Weakness on one side of the body — this is rare and occurs in a specific type called hemiplegic migraine.

Aura symptoms spread gradually over minutes, which distinguishes them from the sudden onset of neurological symptoms seen in stroke. However, any new or unfamiliar neurological symptom should be assessed by a doctor promptly.

Common migraine symptoms

The headache phase of migraine has a characteristic set of features that distinguish it from other headache types. According to ICHD-3 criteria, a migraine attack (without aura) involves at least two of the following pain characteristics:

• Unilateral location (one side of the head)
• Pulsating or throbbing quality
• Moderate or severe intensity
• Worsened by — or causing avoidance of — routine physical activity

During the attack, at least one of the following is also present:

• Nausea and/or vomiting
• Photophobia (sensitivity to light) and phonophobia (sensitivity to sound)

Other symptoms people commonly report include osmophobia (sensitivity to smell), difficulty concentrating, and a strong preference for a dark, quiet room. Allodynia — where normal touch, such as brushing hair or wearing glasses, becomes painful — is common in more established attacks and reflects changes in how the nervous system processes sensation.

What causes migraines? Triggers vs underlying mechanism

Migraine has a strong genetic component. First-degree relatives of people with migraine are approximately three times more likely to have migraine themselves (Pescador Ruschel & De Jesus, StatPearls, 2024). The precise mechanism involves abnormal brain activity affecting nerve signals, neurochemicals — particularly serotonin and calcitonin gene-related peptide (CGRP) — and altered processing of pain signals in the trigeminal system (Eigenbrodt et al., Nature Reviews Neurology, 2021).

A useful distinction is between the underlying susceptibility (the brain's inherited tendency to generate attacks) and triggers (factors that tip a susceptible brain into an attack). Triggers do not cause migraine in people who do not have the underlying condition. Common triggers include:

• Stress (reported by up to 80% of people with migraine)
• Hormonal changes — particularly falling oestrogen levels around menstruation
• Sleep changes — too much or too little
• Skipping meals or dehydration
• Bright or flickering lights, strong smells
• Weather or barometric pressure changes
• Alcohol, particularly red wine

Identifying your personal triggers through consistent tracking is one of the most clinically useful things you can do. HeadacheRecovery's journal is designed to help you record this data in a structured way to share with your doctor — it does not diagnose migraine or identify triggers for you. See our guide on what to track in a headache diary for a practical starting point.

Types of migraine

The ICHD-3 classifies several distinct migraine subtypes:

• Migraine without aura: The most common type, accounting for around 75% of diagnoses (Pescador Ruschel & De Jesus, StatPearls, 2024). Recurrent attacks meeting the criteria above, with no aura phase.
• Migraine with aura: Attacks preceded or accompanied by fully reversible neurological symptoms as described above.
• Chronic migraine: Headache occurring on 15 or more days per month for more than three months, with migraine features on at least 8 of those days (ICHD-3).
• Vestibular migraine: Recurrent episodes of vertigo (a spinning sensation), dizziness, or balance problems associated with migraine. May occur with or without head pain. Diagnosed using criteria developed jointly by the IHS and the Bárány Society.
• Retinal migraine (sometimes called ocular migraine): Repeated episodes of visual disturbance or temporary loss of vision in one eye only, associated with migraine headache. This is distinct from visual aura, which affects both eyes. Retinal migraine is rare and should always be assessed by a doctor to rule out other causes of monocular vision loss.
• Hemiplegic migraine: A rare subtype involving temporary motor weakness on one side of the body as part of the aura. Often has a genetic component.

How migraine differs from a regular headache

The most important differences are complexity, duration, and associated symptoms. A tension-type headache — the most common primary headache — is typically bilateral (both sides), pressing or tightening in quality, mild to moderate, and not made worse by physical activity. It does not usually cause nausea or significant light and sound sensitivity.

Migraine is disabling by definition. An attack interrupts normal functioning. The pain is moderate to severe, often one-sided and throbbing, worsened by movement, and accompanied by nausea or sensory sensitivities. The four-phase structure, the postdrome, and the existence of aura have no equivalent in tension-type headache.

This distinction matters for management. Treatments that help tension-type headache may not adequately manage migraine, and vice versa. An accurate diagnosis from a clinician — based on history against ICHD-3 criteria — is the starting point for effective care. Our guide on migraine vs tension-type headache goes deeper on this comparison.

The burden of migraine: what the evidence shows

The impact of migraine on daily life is substantial and extends far beyond the hours of an attack. Migraine is associated with lost social plans, missed work, strained relationships, and long-term effects on career and quality of life — costs that statistics alone do not fully capture.

From an economic standpoint, people with migraine incur total annual healthcare and productivity costs approximately $8,924 higher than matched individuals without migraine (Bonafede et al., Headache, 2018). Across OECD countries, direct costs — particularly hospitalisation and medication — are consistently identified as the highest contributors to the economic burden. Indirect costs from absenteeism (days missed from work) and presenteeism (reduced productivity while present) are frequently underestimated (Khanal et al., Health Economics Review, 2023).

Access to good-quality care is an additional layer of the burden. Evidence from primary care research shows that many people with migraine receive suboptimal care — with under-use of effective treatments such as triptans and preventive therapies, and high rates of medication-overuse headache (Hind et al., BJGP Open, 2025). In the UK, specialist headache clinic waiting times increased from 15 to 29 weeks between 2021 and 2023, and only 62% of integrated care systems in England have a specialist headache clinic at all (Hind et al., 2025). These systemic gaps make self-management skills and structured tracking all the more important for people living with migraine.

The Eigenbrodt et al. (2021) consensus statement — endorsed by the European Headache Federation and the European Academy of Neurology — explicitly emphasises patient-centred care and patient education as essential to improving treatment adherence and satisfaction. This aligns directly with the rationale behind HeadacheRecovery: building the skills and data to engage more effectively with clinical care, not to replace it.

When to seek medical advice