Cutaneous responses to vasoactive intestinal polypeptide in chronic idiopathic urticaria.

Cutaneous wheal and flare responses to increasing concentrations of calcitonin gene-related peptide, substance P, neurokinin A, vasoactive intestinal polypeptide (VIP), compound 48/80, and phosphate-buffered saline were measured in 10 patients with chronic idiopathic urticaria and 10 healthy controls. A significant increase in VIP-induced wheal, but not flare or cutaneous blood flow, was seen in urticarial patients compared with controls (p less than 0.001). No significant differences in responses to other tested compounds were found between these groups. These data point to an increased sensitivity of microvasculature to VIP in patients with chronic idiopathic urticaria.