Have you ever had the experience of walking through a local department store only to be overcome by a pulsating, throbbing headache as the smell of perfume wafts into your nostrils? We know that people who suffer from migraines consistently report environmental factors such as weather, noise, light exposure, and altitude as triggers. Odors, too, can spark migraines.What odors typically trigger a migraine?
Sensitivity to smell is common in the general population and can manifest as a headache — and more specifically, a migraine — in those who are predisposed. One study in Italy found that 46% of young food store workers reported feeling ill after being exposed to several chemical materials, with headache being the most common symptom reported. The most problematic odors reported in the study were car exhaust and pesticides. Many other common odors have also been reported to trigger migraines, including: perfumes, foods, tobacco smoke, asphalt, carpeting, paint thinners, detergents, combustible gas and many more.What about those smells you experience during a migraine?
Smell can certainly play a role in triggering migraines, but it can also be part of the attack itself. During a migraine, you may have noticed an increased sense of smell or a desire to avoid a smell. This is called osmophobia, and is one of the alternate criteria for diagnosing migraine without aura in the 2nd edition of the International Headache Classification (ICHD-2).
One study by a group of Italian researchers (Zanchin et al) found that a little over 40% of 800 patients with migraines reported that they could not tolerate certain smells during a migraine attack. The most bothersome smell was perfume/cologne, followed by foods and cigarette smoke.
This olfactory (sense of smell) hypersensitivity may also occur between migraine attacks. In one study by Demarquay in Cephalalgia, of 74 patients with migraines and 30 subjects without migraines, the patients with migraines were more likely to report olfactory or smell hypersensitivity between migraine attacks. These patients with olfactory hypersensitivity were also more likely to have odor-triggered migraines and a higher frequency of migraines than those without olfactory hypersensitivity.How does odor trigger a migraine?
This is a complex question, as a migraine itself is a complicated medical process. In an article in Toxicology, Miller has suggested there are two stages of chemical sensitivity proposing that stage one involves the loss of tolerance for a chemical smell, and stage two involves the onset of a migraine by re-exposure to the previously tolerated chemical. This is similar to an allergic response where an individual's intolerance for a substance can occur after an initial exposure, or after multiple exposures.What can I do?
Remember that awareness of your triggers, and avoidance of them, are key to migraine prevention. Here are some ideas to consider when identifying your triggers:• Create a headache diary to see if certain odors are triggering your migraines.
• Write down or record in your phone any perceived smells you have prior to or during a migraine attack to see if there are common links.
• See your healthcare provider and have an open, honest conversation about what you think your potential triggers are. Share you diary with her.
• Take charge of your environment. For example, if you discover perfume is a trigger, consider discussing a perfume-free workplace with your boss or roommate. Avoid social situations with individuals who smoke if this is a potential trigger.
Demarquay G, Royet JP, Giraud P, Chazot G, Valade D, Ryvlin P. "Rating of olfactory judgements in migraine patients." Cephalalgia. 2006;26(9):1123-30.
Friedman DI, De ver Dye T. "Migraine and the Environment." Headache. 2009 Jun;49(6):941-52.
Magnavita N. "Cacosmia in healthy workers." Br J Med Psychol. 2001 Mar;74(Pt 1):121-7.
Miller CS. "Chemical sensitivity: Symptom, syndrome, or mechanism for disease?" Toxicology. 1996 July;111(1-3):69-86.
Zanchin G, Dainese F, Trucco M, Mainardi F, Mampreso E, Maggioni F. "Osmophobia in migraine and tension-type headache and its clinical features in patients with migraines." Cephalalgia. 2007 Sept;27(9):1061-8.