What Is Urticaria Pigmentosa and How Is It Managed?

Urticaria pigmentosa — also known as maculopapular cutaneous mastocytosis (MPCM) — is an itchy rash that shows up most often in children and young adults. The rash may look reddish-brown, gray, purplish, or tan, depending on your skin tone. It may turn into hives or blisters when you rub or scratch it. This reaction is called Darier’s sign.