OverviewUrticaria pigmentosa is characterized by few to many brownish spots which itch and, when scratched, produce welts and reddened skin. The brown spots contain cells with high levels of histamine. Individuals sometimes develop flushing and headache resulting from the massive release of histamine from these spots. This is the typical appearance of one of these spots (often referred to as a mastocytoma).
Review Date 10/31/2016
Updated by: Kevin Berman, MD, PhD, Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.