Migraine may be a risk factor for the development of complex regional pain syndrome.

The aim was to assess the relative frequency of migraine and the headache characteristics of complex regional pain syndrome (CRPS) sufferers. CRPS and migraine are chronic, often disabling pain syndromes. Recent studies suggest that headache is associated with the development of CRPS. Consecutive adults fulfilling International Association for the Study of Pain criteria for CRPS at a pain clinic were included. Demographics, medical history, and pain characteristics were obtained. Headache diagnoses were made using International Classification of Headache Disorders, 2nd edn criteria. Migraine and pain characteristics were compared in those with migraine with those without. anova with Tukey post hoc tests was used to determine the significance of continuous variables and Fisher's exact or χ(2) tests for categorical variables. The expected prevalence of migraine and chronic daily headache (CDH) was calculated based on age- and gender-stratified general population estimates. Standardized morbidity ratios (SMR) were calculated by dividing the observed prevalence of migraine by the expected prevalence from the general population. The sample consisted of 124 CRPS participants. The mean age was 45.5 ± 12.0 years. Age- and gender-adjusted SMRs showed that those with CRPS were 3.6 times more likely to have migraine and nearly twice as likely to have CDH as the general population. Aura was reported in 59.7% (74/124) of participants. Of those CRPS sufferers with migraine, 61.2% (41/67) reported the onset of severe headaches before the onset of CRPS symptoms Mean age of onset of CRPS was earlier in those with migraine (34.9 ± 11.1 years) and CDH (32.5 ± 13.4 years) compared with those with no headaches (46.8 ± 14.9 years) and those with tension-type headache (TTH) (39.9 ± 9.9 years), P < 0.05. More extremities were affected by CRPS in participants with migraine (median of four extremities) compared with the combined group of those CRPS sufferers with no headaches or TTH (median 2.0 extremities), P < 0.05. The presence of static, dynamic and deep joint mechano-allodynia together was reported by more CRPS participants with migraine (72.2%) than those with no headaches or TTH (46.2%), P ≤ 0.05. Migraine may be a risk factor for CRPS and the presence of migraine may be associated with a more severe form of CRPS. Specifically: (i) migraine occurs in a greater percentage of CRPS sufferers than expected in the general population; (ii) the onset of CRPS is reported earlier in those with migraine than in those without; and (iii) CRPS symptoms are present in more extremities in those CRPS sufferers with migraine compared with those without. In addition, as we also found that the presence of aura is reported in a higher percentage of those CRPS sufferers with migraine than reported in migraineurs in the general population, further evaluation of the cardiovascular risk profile of CRPS sufferers is warranted.