Clinical correlates and diagnostic utility of osmophobia in migraine

Background: Osmophobia is an under-investigated associated symptom in migraine. Objective: To evaluate the clinical correlates and diagnostic utility of osmophobia. Methods: Adult patients with migraine (with or without aura), probable migraine (PM), tension-type headache (TTH), and cluster headache (CH) were recruited retrospectively from our headache registration system. Migraine patients with and without osmophobia were compared. The newly proposed criteria for migraine requiring at least two of photo-, phono-, or osmophobia instead of both photo-and phonophobia were validated. Results: In total, 2883 patients were included: 1809 migraine, 792 PM, 138 TTH, and 144 CH. Osmophobia was more common in migraine (62.2%) than in PM (33.8%), TTH (14.5%), and CH (31.3%) (all p<0.001). Migraine patients with osmophobia scored higher on the Hospital Anxiety and Depression Scale (HADS) than those without (15.6 +/- 7.6 vs. 13.3 +/- 7.8, p<0.001). The concordance in headache diagnoses between ICHD-2 (International Classification of Headache Disorders, Second Edition) and the newly proposed criteria was almost perfect (kappa = 0.886, p<0.001). Additionally, 16.9% of ICHD-2 PM patients were reclassified as migraine using the newly proposed criteria. Conclusions: Osmophobia was prevalent in migraineurs, and was associated with higher HADS scores. The newly proposed criteria appear comparable to the ICHD-2 criteria, and may increase the diagnostic yield for Asian migraineurs, among whom photophobia was less common.