Cutaneous allodynia as a predictor of migraine chronification.

Cutaneous allodynia is a common feature accompanying migraine attacks and considered a clinical marker for central sensitization. In a longitudinal study, we wanted to investigate if allodynia in migraine patients is a predictor of increasing frequency of migraine days. We included 3029 well-defined, web-based migraine patients (86% female, mean age 42.8 ± 11.4 years, 61% migraine without aura). Questionnaires on migraine characteristics (including allodynia), depression and demographic factors were applied. The number of migraine days was measured twice. Multivariate regression models were used, with correction for other factors that are involved in the relation between allodynia and the number of migraine attacks or migraine days, with specific focus on depression. Of all 2331 eligible migraine patients, 1624 (70%) had allodynia. Lifetime depression was an independent risk factor for allodynia (odds ratio 1.52, 95% confidence interval 1.26-1.84), as well as female gender, low age at onset, and high migraine attack frequency. Analysis of the longitudinal data (in migraineurs with a follow-up period of >6 months) showed that, apart from the known risk factors (low age at onset, high baseline number of migraine days, and depression), allodynia was an independent predictor for increase in number of migraine days over a mean follow-up period of 93 ± 30 weeks (median 103 weeks, range 26-160 weeks). Cutaneous allodynia is a risk factor for migraine chronification and may warrant preventive treatment strategies.