ICHD-3. Cephalalgia. 2018;38:1–211. PMID 29368949¶
Why this paper matters¶
ICHD-3 is the operational language of modern headache research. It specifies attack counts, durations, symptom combinations and exclusion clauses, and it determines who enters most migraine trials. It is a phenomenological classification, not a biomarker-derived taxonomy.
Load-bearing definitions¶
| Entity | Operational core |
|---|---|
| Migraine without aura | ≥5 attacks, 4–72 hours, ≥2 characteristic pain features and nausea/vomiting or photophobia plus phonophobia |
| Migraine with aura | ≥2 attacks with fully reversible focal symptoms and ≥3 specified temporal/phenotypic characteristics |
| Chronic migraine | ≥15 headache days/month for >3 months, with migraine features or migraine-specific response on ≥8 days |
| Medication-overuse headache | ≥15 headache days/month plus >3 months of class-threshold acute-medication overuse |
Interpretation¶
- “Episodic” is the complement of the chronic threshold; it is not a separate biological diagnosis.
- Migraine and medication-overuse headache can and should be coded together when both criteria are met.
- Probable migraine is useful when one required feature is missing.
- Aura criteria improve reproducibility but do not make every qualifying first focal event safe to diagnose without secondary-cause assessment.
Limitations¶
- Thresholds create categorical trial populations from continuous frequency and disability distributions.
- Patient recall can misclassify duration, aura evolution and medication days.
- Criteria do not replace examination or evaluation of red flags.
- Appendix entities signal uncertainty and should not be treated as equally established diagnoses.
Knowledge-base use¶
Primary anchor for classification-and-diagnosis.md, chronic-migraine-and-chronification.md, medication-overuse-headache.md, and the overview.