Alcohol as a dietary trigger of primary headaches: what triggering site could be compatible?

Alcoholic drinks (AD) have been known as migraine triggers in about one-third of migraine patients in retrospective studies. We have reviewed the studies concerning the role of AD in triggering the various types of primary headaches published after the International Headache Society classification of 1988. There are many studies showing that AD are triggers of migraine without aura (MO), migraine with aura (MA), cluster headache (CH) and tension-type headache (TH). About one-third of MO and half of CH patients reported AD as trigger factors. Some studies show that AD are triggers in MA and TH in a similar percentage to that found in MO, but there are also discordant findings. There are sparse reports that AD are also triggers of less frequent types of primary headache such as familial hemiplegic migraine, hemicrania continua and paroxysmal hemicrania. The mechanism of alcohol-provoking headache is debated and should be compatible with the principal pathogenetic theories of primary headaches. If AD are capable of triggering practically all primary headaches, they should act at a common pathogenetic level. Vasodilatation is unlikely to be compatible as common mechanism. An action at cortical or more likely at subcortical level is plausible.