• Clinical science



Headache is a commonly presenting complaint in everyday clinical practice, and, according to the WHO, one of the ten most common causes of functional disability. It may be primary (e.g., tension-type headaches, migraine) or secondary (e.g., following head trauma or infections) in nature. Headache may occur as acute episodes or persist chronically. Chronic headaches, which are associated with a decline in quality of life, have a significant socioeconomic impact. Therefore, chronic headaches should be diagnosed and treated early. Although most episodes of headache are fleeting and harmless, one must always consider potentially life-threatening causes (e.g., subarachnoid hemorrhage, meningitis). Identifying the cause of headaches is often difficult, and requires a detailed clinical history as well as a thorough physical examination. Additional investigation, such as cranial imaging, is only indicated if headache persists despite treatment or when specific clinical features are present that are signs of an underlying disease. This learning card gives an overview of the most common types of headache and serves as a guide to diagnosing different headache disorders.


  • Distribution: Headache is a global health problem that affects people of all ages, ethnicities, and regions.
  • Worldwide prevalence: 60%
  • Most common forms of headache
    • Tension-type headache: 60–80% of cases
    • Migraine: 12–14% of cases


Epidemiological data refers to the US, unless otherwise specified.


Type of headache Common causes

Primary headache

Secondary headache

Head and/or cervical trauma
Vascular disorders in the head and neck region
Non-vascular intracranial disorders
Introduction or withdrawal of a substance
Disorders of homeostasis
Disorders of the eyes, teeth, nasal cavity, neck, and/or paranasal sinuses
Psychiatric disorders
Cranial nerve neuralgias and facial pain
Headaches that do not fit any of the patterns above or have an unknown cause are referred to as “unclassified headache disorders.”


Clinical features

Clinical history

  • Duration of a single episode
  • Frequency (number of episodes per month)
  • Clinical course (e.g., chronic , acute)
Nature of headache
  • Localization (e.g., unilateral, bilateral, orbital)
  • Character (e.g., pulsating, stabbing)
  • Intensity (rated on a pain scale ranging from 0 to 10)
Triggers and exacerbating factors
  • Altered sleep-wake cycle
  • Physical exertion
  • Stress
  • Certain types of food, alcohol
  • Fluctuations in hormone levels: oral contraceptives, menstruation
  • Lying down or standing up
Concomitant symptoms
Other relevant aspects

Physical examination

A detailed clinical history helps to identify the underlying cause of headache, especially when neurological examination is normal (e.g., primary headaches)!

A thorough physical examination is important to identify the cause of secondary headache!



Additional diagnostic tests should be undertaken if any of the following red flags are present:
Imaging Additional tests

Diagnostic tests are usually not indicated in most cases (especially primary headaches). They are used primarily to evaluate secondary headaches and severe, acute headaches, which may be life-threatening (e.g., subarachnoid hemorrhage, trauma)!

The investigation of choice is determined by the clinical presentation!

Differential diagnoses

Primary headaches

Tension headache Migraine Cluster headache
  • <
  • <
  • > (3:1)
  • Episodic or chronic
  • 4–72 hours
  • 30–180 min
  • Occasionally to daily
  • Occasionally to several times a month
  • 1–3 episodes/24 h
  • Holocephalic or bifrontal
  • 60% are unilateral
  • Mostly unilateral
  • Compressive, non-pulsating dull pain (band-like)
  • Pulsating, boring/hammering pain
  • Severe headache that is localized to the periorbital region
  • Mild to moderate
  • Moderate to severe
  • Severe
Additional symptoms No additional autonomic symptoms
  • Ipsilateral conjunctival injection and/or epiphora (excessive lacrimation)
  • Rhinorrhea and swelling of nasal mucous membranes
  • Partial horner syndrome (ptosis, miosis)
  • Ipsilateral forehead or facial sweating
Triggers/exacerbating factors
  • Stress
  • Lack of sleep, fatigue
  • Stress
  • Fluctuation in hormone levels: oral contraceptives, menstruation
  • Certain types of food (e.g., those containing tyramines or nitrates such as processed meat, chocolate, cheese)
  • Physical exertion
  • Alcohol

Secondary headache

The following table deals with secondary causes of headaches, some of which are life-threatening but treatable and should therefore be diagnosed as early as possible.

Causes Diagnosis Type of headache Additional clinical features
Infections Meningitis
  • Dull, diffuse (holocephalic) headache that worsens over hours/days
  • Acute, diffuse headache that worsens over time
Vascular causes Intracranial hemorrhage
  • Vomiting
  • Rapidly worsening neurological status
  • Focal neurological deficits
  • Seizures
  • Horizontal gaze palsy
  • Spasmodic torticollis (with the head turned towards the side of the lesion)
  • Epidural and/or subdural hemorrhage: diffuse headache which worsens over time (the pain is worst on the side of intracranial hemorrhage)
  • Impaired consciousness
  • Signs of increased intracranial pressure
  • Ipsilateral mydriasis
  • Possibly focal neurological deficits
  • Epidural hemorrhage: initial loss of consciousness → symptomless lucid interval during which the patient regains consciousness → loss of consciousness for the second time
  • Chronic subdural hemorrhage
    • Psychomotor impairment
    • Memory loss
Cerebral venous sinus thrombosis
  • Mostly nonspecific complaints: subacute onset; a dull, diffuse headache that increases in intensity over hours/days
Temporal arteritis
  • Boring, temporal headache that is synchronous with the arterial pulse
Hypertensive crisis/ hypertensive emergency
  • Diffuse (sometimes bifrontal), pulsating headache that is exacerbated by physical activity
  • 25% of all cases present with acute headache (most commonly tension-type, less frequently migrainous or a mixed type)
  • Focal neurological deficits
  • Possibly impaired consciousness
Tumors Intracranial space-occupying lesion (e.g., brain tumors)
  • A dull headache that is usually bifrontal and worsens over weeks/months
Trauma Traumatic brain injury
  • Headache of variable intensity
  • Possibly loss of consciousness
  • Possibly focal neurological deficits
Other causes Glaucoma
  • Severe, unilateral headache
  • Impaired vision
  • Eye pain
  • Nausea, vomiting
  • A stony hard eyeball that is tender to touch
Medication-overuse headache
  • Dull, long-lasting headache

Consider secondary life-threatening causes if red flags are present!


The differential diagnoses listed here are not exhaustive.

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last updated 12/04/2019
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