Headache
Checking Date & Time
Asking for Preferences
Reading File
Finding Sources
Finding Sources
Reading File
Reading File
Reading File
Reading File
Reading File
Here is a comprehensive overview of headache classification, drawn from multiple authoritative sources.
Headache: Overview & Classification
What Is Headache?
Headache is among the most common reasons patients seek medical attention and is responsible, globally, for more disability than any other neurologic problem. Diagnosis rests on careful clinical history, neurologic examination, and understanding of the anatomy and physiology of pain pathways. — Harrison's Principles of Internal Medicine 22E, p. 157
The ICHD-3 Framework
The International Classification of Headache Disorders, 3rd Edition (ICHD-3, 2018) — developed by the International Headache Society — is the universal standard. It organizes headaches into four parts: — Bradley and Daroff's Neurology in Clinical Practice
Part 1: Primary Headaches
Headache is the disorder itself — no underlying disease
| # | Category |
|---|---|
| 1 | Migraine |
| 2 | Tension-type headache |
| 3 | Trigeminal autonomic cephalgias (TACs) (incl. cluster headache) |
| 4 | Other primary headache disorders |
Migraine subtypes (ICHD-3)
- Without aura
- With aura (typical, brainstem, hemiplegic, retinal)
- Chronic migraine
- Complications: status migrainosus, migrainous infarction, aura-triggered seizure
- Episodic syndromes associated with migraine (cyclical vomiting, abdominal migraine, benign paroxysmal vertigo)
Tension-type headache subtypes
- Infrequent episodic
- Frequent episodic
- Chronic
Trigeminal Autonomic Cephalgias (TACs)
- Cluster headache
- Paroxysmal hemicrania
- Short-lasting unilateral neuralgiform headache attacks (SUNHA/SUNA)
- Hemicrania continua
Part 2: Secondary Headaches
Head pain is a symptom of an underlying disorder
| Code | Attributed to… |
|---|---|
| 5 | Trauma or injury to head/neck |
| 6 | Cranial or cervical vascular disorder (SAH, dissection, CVT, RCVS) |
| 7 | Nonvascular intracranial disorder (IIH, low CSF pressure, neoplasm) |
| 8 | Substance use or withdrawal |
| 9 | Infection (meningitis, encephalitis, systemic infection) |
| 10 | Disorder of homeostasis (hypoxia, hypertension, dialysis) |
| 11 | Disorder of cranium, neck, eyes, ears, sinuses, teeth, or TMJ |
| 12 | Psychiatric disorder |
Part 3: Painful Cranial Neuropathies & Other Facial Pain
- Trigeminal neuralgia, glossopharyngeal neuralgia, other cranial neuralgias
Epidemiology at a Glance (Population-Based Data)
| Type | Prevalence (%) |
|---|---|
| Tension-type | 69% of all headache |
| Migraine | 16% |
| Systemic infection (secondary) | 63% of secondary |
| Cluster | 0.1% |
| Brain tumor (secondary) | 0.1% |
Source: Olesen et al., The Headaches; cited in Harrison's
Anatomy of Pain: Why Headaches Happen
The key structures involved in primary headache generation: — Harrison's, p. 157–158
- Large intracranial vessels & dura mater + peripheral terminals of the trigeminal nerve (the trigeminovascular system)
- Trigeminocervical complex — caudal trigeminal nucleus extending into C1–C2 dorsal horns
- Rostral pain-processing regions — ventroposteromedial thalamus and cortex
- Pain-modulatory systems — hypothalamus and brainstem (influence autonomic features of attacks)
The ventricular ependyma, choroid plexus, pial veins, and most brain parenchyma are not pain-producing.
Red Flags — When to Worry (SNOOP4 features)
These symptoms suggest a serious secondary cause requiring urgent workup: — Harrison's, Table 17-2
| Warning Feature |
|---|
| Sudden-onset ("thunderclap") headache |
| First or worst headache of life |
| Vomiting that precedes headache |
| Subacute worsening over days to weeks |
| Pain triggered by Valsalva (bending, coughing, lifting) |
| Pain that wakes from sleep or is present on awakening |
| Onset after age 55 |
| Fever or unexplained systemic signs |
| Abnormal neurologic examination |
| Local tenderness (e.g., temporal artery) |
Quick Clinical Profiles of the Major Primary Headaches
| Feature | Migraine | Tension-type | Cluster |
|---|---|---|---|
| Quality | Throbbing/pulsating | Dull, pressure ("band") | Severe, boring, stabbing |
| Location | Unilateral (often) | Bilateral | Unilateral, periorbital |
| Duration | 4–72 hours | 30 min – 7 days | 15–180 minutes |
| Autonomic features | N/V, photo/phonophobia | None/mild | Ipsilateral tearing, ptosis, rhinorrhea |
| Activity | Worsened by movement | Not worsened | Restlessness/agitation |
| Sex predominance | Female > Male | Equal | Male > Female (4:1) |
| Triggers | Many (hormones, sleep, food) | Stress, posture | Alcohol, circadian (nocturnal) |
Sources: Harrison's Principles of Internal Medicine 22E, p. 157–158 | Bradley and Daroff's Neurology in Clinical Practice | Neuroanatomy through Clinical Cases, 3rd Ed., p. 165
This is a shared conversation. Sign in to Orris to start your own chat.