VIP and migraine disorder: Vasoactive neuropeptides mainly derived from nerve cells, such as pituitary adenylate cyclase-activating peptide (PACAP) and migraine-associated calcitonin gene-related peptide (CGRP), are upregulated in rosacea skin, and vasoactive intestinal peptide (VIP) receptor–positive cells distribute more densely within the endothelium of patients with rosacea (20–23).