What is Headache Syndrome?
Headache syndrome refers to a clinical pattern of pain or discomfort in the head or face region, classified into primary headache disorders (where the headache itself is the disease) or secondary headache disorders (where an underlying pathologic condition causes the headache). 1, 2
Primary vs. Secondary Classification
Primary headache disorders constitute approximately 98% of all headaches and include migraine, tension-type headache, cluster headache, and other primary headache disorders—these have no underlying pathologic cause and the headache itself is the disease entity. 3, 2, 4
Secondary headache disorders result from underlying pathologic causes including head/neck trauma, cranial or cervical vascular disorders, nonvascular intracranial disorders, substance use or withdrawal, infection, and disorders of homeostasis. 2
The Three Major Primary Headache Syndromes
Migraine Syndrome
Characterized by recurrent moderate-to-severe unilateral, pulsating headache lasting 4-72 hours with nausea/vomiting, photophobia, and phonophobia that worsens with routine physical activity. 1
Affects 18% of women and 6.5% of men in the United States, making it the second leading cause of years lived with disability worldwide. 3, 2, 5
Migraine with aura includes recurrent short-lasting visual, sensory, speech/language, motor, brainstem, or retinal symptoms preceding or accompanying the headache. 1
Chronic migraine is defined as ≥15 headache days/month for >3 months, with ≥8 days meeting migraine criteria. 1
Tension-Type Headache Syndrome
Presents as bilateral, mild-to-moderate pressing or tightening quality pain that lacks migraine features and is not aggravated by routine physical activity. 1, 6
Affects 38% of the population, making it the most prevalent headache type, though less disabling than migraine. 5
Generally lacks nausea/vomiting (though may have anorexia) and typically doesn't have both photophobia and phonophobia. 6
Cluster Headache Syndrome
Strictly unilateral severe headache lasting 15-180 minutes with ipsilateral autonomic symptoms including lacrimation, conjunctival injection, nasal congestion, ptosis, and miosis. 1
Requires five attacks with frequency of 1-8 attacks per day and affects approximately 0.1% of the general population. 2
Critical Diagnostic Principle
The International Headache Society classification system diagnoses headache syndromes, not patients—meaning one patient can have more than one type of headache disorder simultaneously (e.g., a patient with migraine can also have episodic tension-type headaches). 3, 2
Impact and Burden
Headache disorders affect approximately 90% of people during their lifetime, with a lifetime prevalence of 66%. 3, 5
Headache is the second leading cause of years lived with disability across all age groups, and more disability-adjusted life-years are attributed to headache than to all other neurologic disorders combined. 3
Health-related quality-of-life scores are consistently lower among those living with migraine than among headache-free, age-matched controls, with pain intensity, headache frequency, associated symptoms, comorbid conditions, stigma, and catastrophizing as significant contributors to disability. 3
In the United States, indirect and direct medical costs for migraine alone are approximately $36 billion annually, mainly attributed to missed work days (absenteeism) and impaired work function during headache (presenteeism). 3
When Secondary Causes Must Be Considered
Red flags requiring investigation for secondary headache disorders include thunderclap headache ("worst headache of life"), new-onset headache after age 50, progressive worsening headache, atypical aura with focal neurological symptoms, recent head/neck trauma, headache awakening patient from sleep, headache brought on by Valsalva/cough/exertion, focal neurological symptoms/signs, unexplained fever, neck stiffness, altered consciousness/memory/personality, and witnessed loss of consciousness. 1, 2