Migraines and other headaches: an approach to diagnosis and classification.

Headache is a symptom that accounts for over 18 million visits to physicians each year. In an effort to resolve inconsistencies and problems with the differentiation of specific types of headache, the International Headache Society (IHS) has established a classification system. For each major type of headache, the IHS classification specifies diagnostic criteria and recognized subtypes where appropriate. Migraine headaches are commonly encountered in clinical practice. Recognition and accurate diagnosis of migraine headache depend on a thorough history, appropriate physical examination and diagnostic testing.