Prevalence of migraine headaches in patients with allergic rhinitis

Background: Histamine has been implicated in the pathogenesis of migraine headaches. Because allergic rhinitis (AR) is a histamine-driven syndrome and the nasal passage is in close proximity to the central nervous system, we hypothesize that AR may trigger migraine headaches. Objective: To determine the prevalence of migraine headaches in patients with and without AR. Methods: Allergic rhinitis was diagnosed based on skin or radioallergosorbent test results, clinical history, and physical examination findings. The diagnosis of migraine headache was made if patients fulfilled the International Headache Society criteria. Surveys were obtained from hospital-based allergy, pediatric, and internal medicine clinics, all serving the same inner-city population. Results: A total of 294 surveys were completed. Of 76 patients in the AR group, 26 (34%) had headaches meeting the International Headache Society criteria for migraines, and of the 57 patients in the non-AR group, only 2 (4%) had headaches that met the criteria. A Fisher exact test showed P = 8.2 × 10 ^-6. The odds ratio was 14.3, which signifies that the odds of having migraine headaches is 14.3 times higher in the AR group than in the non-AR group. Conclusions: There is a high prevalence of migraine headaches in patients with AR compared with those without AR. We propose that histamine plays a key role in triggering migraines by means of vasodilation and inflammation in the pathogenesis of migraine headaches.