Print Friendly and PDF
► Urticaria pigmentosa - close-up

Urticaria pigmentosa - close-up

Urticaria pigmentosa is characterized by several to many brownish spots that itch and, when scratched, produce welts and reddened skin. The brown spots contain mast cells with high levels of histamine. People sometimes develop generalized flushing and headaches from the massive histamine release from these spots.