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Chronic Migraine: Diagnosis and Prevention

Chronic Migraine: Understanding the Condition and Specialist Treatment Pathways

Migraine is a neurological disorder characterised by recurrent attacks of headache and associated symptoms.

For some individuals, migraine becomes sufficiently frequent to interfere substantially with employment, family life and everyday activities.

When headaches occur on at least 15 days per month for more than three months, with migraine features on at least eight days per month, the condition may meet the diagnostic criteria for chronic migraine.

How does migraine develop?

Migraine involves complex interactions between neural pathways, sensory processing and pain signalling.

The trigeminovascular system plays an important role in migraine biology.

Neuropeptides, including calcitonin gene-related peptide (CGRP), are involved in pathways associated with migraine attacks.

However, migraine is not simply caused by excessive muscle tension or changes in blood vessel diameter.

Chronic versus episodic migraine

Episodic migraine involves fewer than 15 headache days per month.

Chronic migraine involves more frequent headache activity and may be associated with a substantial reduction in quality of life.

Accurate diagnosis requires consideration of headache frequency, associated symptoms, medication use and alternative causes.

A headache diary can be particularly helpful.

How is chronic migraine managed?

Management typically combines education, identification of relevant triggers, appropriate acute medication and preventive strategies.

Preventive medicines may be considered when attacks are frequent or disabling.

Options depend on the individual’s medical history, contraindications, previous treatment responses and current clinical guidance.

Medication-overuse headache must also be considered because frequent use of acute headache medicines can contribute to persistent symptoms.

The role of specialist injectable medicines

Some prescription-only injectable medicines have an established role in the prevention of chronic migraine.

NICE technology appraisal TA260 recommends botulinum toxin type A as an option for certain adults with chronic migraine when at least three previous preventive treatments have not been effective and medication overuse has been appropriately managed.

This recommendation applies to a defined clinical population and should not be interpreted as a general recommendation for occasional headaches or episodic migraine.

The treatment is distinct from cosmetic applications and requires appropriate specialist assessment and follow-up.

How is treatment response assessed?

Response is generally evaluated using headache frequency and other measures of migraine burden.

NICE guidance includes criteria for discontinuing treatment when an adequate response has not occurred or when headache frequency changes sufficiently that the patient no longer meets the relevant chronic migraine criteria.

This reflects the importance of measurable clinical outcomes rather than relying exclusively on subjective impressions.

When should someone seek urgent medical attention?

A sudden, exceptionally severe headache, new neurological symptoms, fever with neck stiffness or a headache associated with a significant change in consciousness requires urgent medical assessment.

New or progressively worsening headaches also warrant appropriate investigation.

Final thoughts

Chronic migraine is a recognised neurological condition that requires structured diagnosis and individualised management.

Specialist injectable medicines represent one component of established preventive pathways for selected patients, rather than a universal treatment for headaches.

References

• National Institute for Health and Care Excellence (NICE) (2012) Botulinum toxin type A for the prevention of headaches in adults with chronic migraine. Technology appraisal guidance TA260. Available at: https://www.nice.org.uk/guidance/ta260
• National Institute for Health and Care Excellence (NICE) (2012, updated 2025) Headaches in over 12s: diagnosis and management. Clinical guideline CG150. Available at: https://www.nice.org.uk/guidance/cg150