Cutaneous sensory abnormalities in children and adolescents with complex regional pain syndromes.

Complex regional pain syndromes (CRPS) have been recognized with increasing frequency in children. These disorders appear to differ markedly from those observed in adults. The International Association for the Study of Pain diagnostic criteria for CRPS were developed based on adult studies; these criteria have not been validated for children. We performed standardized neurological examination and quantitative sensory testing (QST) in a group of pediatric patients to characterize features of sensory dysfunction. Forty-two patients, with unilateral lower extremity CRPS of a mean duration of the pain and symptoms of 12.6 months, who met IASP adult-based criteria for CRPS underwent standardized neurological examination and QST. QST parameters were compared to values previously derived from age- and sex-matched pediatric healthy controls. In most respects, QST parameters did not differ significantly between patients and the normal reference values except for cold and heat pain detection thresholds. Allodynia to cold and/or heat (P<0.001) occurred in 21 patients. Cold allodynia was the most common QST abnormality in our patients. Twenty-six patients showed a combination of mechanical dynamic and static allodynia and allodynia to punctate temporal summation. There was a significant correlation between mechanical dynamic allodynia and allodynia to punctate temporal summation (P<0.001). As with adult CRPS, the thermal and mechanical sensory abnormalities appear in different combinations in different patients with similar clinical presentations. In a majority of patients, the pathogenesis of pain is seemingly of central origin.