Headache in a variety of forms is one of the most common complaints presenting to the clinician. This is the classification of headache by the International Headache Society (IHS).{1}:

1.0 Migraine	7.0 Headache associated with nonvascular intracranial disorder
2.0 Tension-type headache	8.0 Headache associated with substances or their withdrawal
3.0 Cluster headache and chronic paroxysmal hemicrania	9.0 Headache associated with noncephalic infection
4.0 Other Headaches	10.0 Headache associated with metabolic disorder
5.0 Heachache associated with head trauma	11.0 Headache or facial pain associated with disorder of crnaium, neck, eyes, ears, nose sinuses, teeth, mouth, or other facial or cranial structures
6.0 Headache associated with vascular disorders	12.0 Cranial neuralgias, nerve trunk pain, and deafferentiation pain
	13.0 Headache not classifiable

Olesen J. Headache Classification Committee of the International Headache Society. Classification and diagnostic criteria for headache disorders, cranial neuralgia, and facial pain. Cephalalgia 1988;8(suppl 7):1-96. More detailed listing found in "Troost BT: Migraine and Other Headaches, In Glaser JS: Neuro-Ophthalmology, Lippincott Raven, New York, 2000.

Migraine headaches themselves are classified: