Primary Headache Disorders: Diagnostic Criteria for Migraine, Tension-Type, and TACs

Primary headache disorders are idiopathic clinical entities in which the headache itself constitutes the primary pathological process rather than a symptom of an underlying structural or systemic lesion. Under the International Classification of Headache Disorders 3rd Edition (ICHD-3), primary headaches are organized into four major diagnostic groups: Migraine, Tension-Type Headache (TTH), Trigeminal Autonomic Cephalalgias (TACs), and Other Primary Headache Disorders.

1. Migraine (ICHD-3 Group 1)

Migraine is a common neurological disorder characterized by episodic paroxysms of headache accompanied by autonomic and neurological symptoms.

Diagnostic Criteria Breakdown

• 1.1 Migraine Without Aura:

  • A. At least 5 attacks fulfilling criteria B–D.

  • B. Attack duration of 4–72 hours (untreated or unsuccessfully treated).

  • C. Headache has at least two of the following four features:

    1. Unilateral location

    2. Pulsating quality

    3. Moderate or severe pain intensity

    4. Aggravation by or causing avoidance of routine physical activity (e.g., walking or climbing stairs).

  • D. Accompanied by at least one of the following during the headache:

    1. Nausea and/or vomiting

    2. Photophobia and phonophobia.

  • E. Not better accounted for by another ICHD-3 diagnosis.

• 1.2 Migraine With Aura:

  • Requires at least 2 attacks characterized by fully reversible focal neurological symptoms (visual, sensory, speech/language, motor, brainstem, or retinal).

  • Aura criteria require at least one aura symptom spreading gradually over $\ge$5 minutes, individual symptoms lasting 5–60 minutes, unilateral distribution, and headache onset accompanying or following the aura within 60 minutes.

• 1.3 Chronic Migraine:

  • Defined as headache occurring on $\ge$15 days per month for >3 months, where at least 8 days per month meet criteria for migraine (or are relieved by a triptan/ergot derivative) in a patient with a baseline history of episodic migraine.

2. Tension-Type Headache (ICHD-3 Group 2)

Tension-type headache is the most prevalent primary headache disorder worldwide, characterized by featureless, mild-to-moderate, bilateral head pressure.

TTH Diagnostic Subtypes

• Infrequent Episodic TTH: $<1$ day per month ($<12$ days/year).

• Frequent Episodic TTH: 1–14 days per month for $>3$ months ($\ge 12$ and $<180$ days/year).

• Chronic TTH: $\ge 15$ days per month for $>3$ months ($\ge 180$ days/year).

Core Clinical Characteristics of TTH Attacks

• Duration: 30 minutes to 7 days (or unremitting in chronic forms).

• Pain Quality: Bilateral, pressing or tightening (non-pulsating) quality of mild-to-moderate intensity.

• Physical Activity Effect: Not aggravated by routine physical activity.

• Associated Features: Absence of nausea or vomiting; no more than one of photophobia or phonophobia.

3. Trigeminal Autonomic Cephalalgias (ICHD-3 Group 3)

TACs are characterized by strict unilateral headache accompanied by prominent ipsilateral cranial autonomic features.

Trigeminal Autonomic Cephalalgias (TACs)
 ├── 3.1 Cluster Headache
 ├── 3.2 Paroxysmal Hemicrania
 ├── 3.3 Short-lasting Unilateral Neuralgiform Headache Attacks (SUNCT / SUNA)
 └── 3.4 Hemicrania Continua

TAC Entity	Attack Duration	Attack Frequency	Absolute Indomethacin Response
3.1 Cluster Headache	15–180 minutes	1 every other day to 8 per day	No
3.2 Paroxysmal Hemicrania	2–30 minutes	>5 per day for >50% of time	Yes (Absolute response)
3.3 SUNCT / SUNA	1–600 seconds	$\ge 1$ per day (stabs or saw-tooth)	No
3.4 Hemicrania Continua	Continuous (>3 months)	Continuous with exacerbations	Yes (Absolute response)

Note on Cranial Autonomic Features: TACs share ipsilateral signs including conjunctival injection, lacrimation, nasal congestion, rhinorrhea, eyelid edema, forehead/facial sweating, miosis, or ptosis. Cluster headache and Hemicrania Continua frequently manifest a sense of restlessness or agitation during attacks.

Key Takeaways for Differential Diagnosis

1. Migraine vs. TTH: Migraine is pulsating, unilateral, aggravated by movement, and accompanied by nausea/vomiting or photophobia/phonophobia; TTH is bilateral, pressing, unaffected by activity, and lacks significant nausea.

2. Indomethacin Sensitivity: Paroxysmal Hemicrania and Hemicrania Continua require absolute prevention/resolution by therapeutic doses of indomethacin for diagnosis.

3. SUNCT vs. SUNA: SUNCT requires both conjunctival injection and lacrimation, whereas SUNA requires only one or neither.