Clinical recognition of allodynia in migraine

Allodynia, a manifestation of central sensitization, is not routinely evaluated during clinical interviews even though its therapeutic implications are known.

To assess the frequency and manifestations of allodynia in a clinic-based migraine population.

A total of 295 consecutive International Headache Society migraine patients were evaluated using a semistructured questionnaire.

A total of 157 (53.3%) reported allodynia. A total of 133 (84.7% of those with allodynia) had cephalic, 54 (18%) had both cephalic and extracephalic, and 24 (8.5%) exhibited pure extracephalic allodynia. Prominent scalp symptoms were sensitivity to touch; soreness or tenderness; difficulty brushing, combing, or washing hair; difficulty lying with head resting on the side of allodynia; and circumscribed area of hypersensitivity and tenderness. Scalp allodynia was ipsilateral to predominant headache side in the majority and occurred at the height of headache. Extracephalic allodynia of the upper extremities occurred in 72, toes in 6. Truncal allodynia occurred in some. Age range and age at onset of migraine were identical in allodynic and non-allodynic patients. Patients with allodynia were on an average 8 years older than non-allodynic patients (p < 0.05). Correlation was found between the duration of illness as well as frequency of migraine attacks and allodynia. Frequent migraineurs exhibited prolonged allodynia.

Clinically detectable allodynia, which occurs with high frequency in migraineurs, should become part of the clinical evaluation because of its implications in early treatment with triptans, recurrence of headache, consistency of response to triptans, and development of chronicity of migraine.