trigger factors

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Trigger factors are reported commonly but there is little consistency between patients.

Dietary triggers affect about 20% of people (1).

Most attacks have no obvious trigger, and some triggers that are identified are unavoidable.

Trigger factors include:

  • bright lights
  • certain foods:
    • alcoholic drinks
    • tyramine containing foodstuffs (cheese, citrus fruits, chocolate)
    • food may be considered a trigger when:
      1. migraine onset occurs within 6 hours of consumption
      2. the effect is reproducible
      3. withdrawal leads to improvement
  • extremes of weather (e.g. very hot or cold, strong winds)
  • long distance travel
  • loud noise
  • missing meals
  • strenuous unaccustomed exercise
  • too much or too little sleep
  • emotional stress and anxiety


  1. British Association for the Study of Headache (BASH) guidelines 2004

Last reviewed 05/2019