In addition, injection of AS into the skin of the volar forearm induced a large axon-reflex erythema (Fig. 4c) visualized by laser Doppler scanning of superficial blood flow (Fig. 4e, Supplementary Fig. 6a), which was not affected by the pre-administration of Clemastine, an H1 histaminic receptor blocker, indicating that the AS-induced vasodilation is not due to mast cell degranulation (Supplementary Fig. 6b,c). The gene discussed is HRH1; the disease is Erythema.