Trigger point evaluation in migraine patients: an indication of peripheral sensitization linked to migraine predisposition?

Although migraine is a neurovascular disorder, both scalp tenderness and referred pain have been observed in migraine patients. The present study was carried out to investigate the presence of trigger points eliciting referred pain in 98 migraine patients and in 32 healthy subjects. Trigger points were found in 92 (93.9%) migraineurs and in nine (29%) controls (P < 0.0001). The number of individual migraine trigger points varied from zero to 14 (modal number: 4), and was found to be related to both the frequency of migraine attacks (P < 0.0001), and the duration of the disease (P = 0.017). About 74% of the total detected trigger points were found in temporal and/or suboccipital areas; other locations were mainly found in patients showing more than four trigger points. Trigger point palpation provoked a migraine attack in 30 (30.6%) patients. Pericraneal allodynia was found in 15 (15.3%) patients. These data indicate that nociceptive peripheral sensitization is a usual finding in migraine, and that central sensitization can develop in patients with frequent attacks and long-lasting disease. Trigger points' detection in migraine patients could be useful when applying therapies like acupuncture, needling or botulinum toxin injections directed to reduce peripheral sensitization.