Olfactory symptoms reported by migraineurs with and without auras

Olfaction-related symptoms accompany migraine attacks and some, such as osmophobia, may be useful in differentiating migraine from other types of headaches. However, the types and frequencies of olfactory symptoms associated with migraine have not been well characterized. The goal of this study was to better characterize the olfactory symptoms of migraine.

A cross-sectional study was devised. One hundred and thirteen patients who met the International Classification of Headache Disorders II criteria for migraine were administered a new 65-item questionnaire specifically focused on olfaction-related experiences (eg, odor-related triggers, osmophobia, cacosmia, phantosmia, olfactory hallucinations, olfactory hypersensitivity, and self-perceived olfactory function). Visual analog scale ratings and frequencies were computed and compared between migraineurs with and without auras using t-tests and chi-square analyses.

While osmophobia was present in 95.5% of the patients, the prevalence of other olfaction-related symptoms was much lower (interictal olfactory hypersensitivity [IOH], 14.1%; olfactory hallucinations, 6.2%; phantosmia, 4.4%; cacosmia/euosmia, 2.6%). Migraine was commonly triggered by odors (90.2%), with perfume being the most common trigger (95.1%), followed by cleaning products (81.3%), cigarette smoke (71.5%), and motor vehicle exhaust (70.5%). No significant differences in symptom frequencies were apparent between migraineurs with or without auras (P > .40). Interestingly, patients with IOH reported being less likely to experience osmophobia and odor-triggered crisis than did those without this symptom (respective percentages: 75% vs. 99% and 69% vs. 94%, P ≤ .002). Osmophobia and odor triggered headache were associated with a mild decrease in self-reported olfactory acuity.

Odor-related disturbances were common symptoms of the 113 migraineurs, with nearly all reporting osmophobia. Perfume odor was the most common trigger for the migraine. The reported symptoms did not differ between patients with and without auras. Patients who experienced IOH appeared to fundamentally differ from those who did not experience IOH in terms of the incidence of osmophobia and odor-triggered crisis. Subjects who reported experiencing osmophobia and odor-triggered headache reported having worse olfactory acuity.