Clinical assessement of hyperalgesia and allodynia in episodic migraine versus chronic migraine interictally and ictally

Abstract Allodynia is defined as a pain sensation evoked by stimulation intensities that do not normally evoke pain: hyperalgesia is defined as an increase in pain sensitivity to normally painful stimuli. Allodynia and hyperalgesia can be evoked at sites adjacent or remote from an injury site (secondary hyperalgesia). Secondary hyperalgesia is called touch-evoked pain and can be detected in areas of the skin adjacent to an originating somatic lesion, or in a somatic region remote from an area of visceral damage. Burstein demonstrated that sensitization of second-order trigeminovascular neurons drives the cutaneous allodynia and/or hyperalgesia. Based on those findings, he expected migraine to be associated with central sensitization, the clinical manifestation of which should be extra cranial sensory hypersensitivity.3