Patients with chronic migraine are often hypersensitive to stimuli, including light, sound, and odors. In fact, some researchers believe the aversion to odors, osmophobia, is particularly helpful in a differentiating migraine from other headache disorders. Now, new research suggests that patients with chronic migraine (CM) do not experience a significant change in their sense of smell between migrainous and non-migrainous periods, but they appear more likely to have an abnormal sense of smell at baseline compared to their peers who do not experience migraine.

Alexander Whiting, MD, of the Department of Neurology at Thomas Jefferson University Hospital in Philadelphia, and colleagues studied the sense of smell in 50 individuals with chronic migraine and 50 controls. To test olfactory acuity, researchers employed the University of Pennsylvania Smell Identification Test (UPSIT).

They found that migraineurs performed worse than their peers without migraine. Among migraineurs, 42 of 50 people were bothered by odors compared with only 9 of 50 controls. Additionally, 41 of the 50 migraineurs found more than one listed odor to be extremely bothersome, compared with only 10 of the 50 in the control group. On days when they did not report a migraine, 18 of 48 subjects experienced abnormalities with their sense of smell. During a migraine attack, 14 of 42 experienced such abnormalities. In the control group, however, fewer individuals, (9 of 50) reported problems with their olfactory sense.

The study appeared last month in the journal Headache.