Facilitation of Extracranial Vasodilatation to Limb Pain in Migraine Sufferers

Background: Dilatation of pain-sensitized scalp vessels can cause pain in migraine headache, and extracranial vascular hyperreactivity to psychological stress and head pain could increase susceptibility to attacks.

Objective: To determine whether changes in facial blood flow differed between migraine sufferers and control subjects during painful stimulation of a limb.

Methods: To document changes in facial blood flow, pulse amplitude was monitored with photoelectric pulse transducers from the frontotemporal region of 23 migraine sufferers and 22 age- and sex-matched control subjects before, during, and after immersion of the nondominant hand in ice water at 2 degrees C for 30 seconds. The hand was immersed three times at 4-minute intervals.

Results: Migraine sufferers rated the pain of the ice-water immersion to be more intense and unpleasant than control subjects, and pain radiated further up the arm. Increases in pulse amplitude were greater ipsilateral than contralateral to painful stimulation (25.1 +/- 2.9 vs 13.7 +/- 4.4%; p < 0.01). Pulse amplitude increased over repeated immersions (p < 0.01) and peaked after the hand was removed from the ice water (p < 0.001), more so ipsilaterally than contralaterally (p < 0.001). Pulse amplitude increased 26.3 +/- 4.3% in migraine sufferers compared with 12.6 +/- 4.4% in control subjects (p < 0.05), and this group difference persisted 8 minutes after the final immersion.

Conclusion: Limb pain triggers increases in facial blood flow and might exacerbate the vascular component of headache during attacks of migraine.