Urticaria pigmentosa is a type of skin mastocytosis, which means you have an increased number of mast cells in the skin.1
Urticaria pigmentosa mostly occurs in infants and children and can also occur in older children and adults.1 It usually resolves by adolescence.1
It appears as red or brown patches on the skin, and the affected skin can be swollen. If the patches are rubbed, the mast cells underneath can release histamines and other chemicals, resulting in itchy hives.1
Urticaria Pigmentosa. Image used with permission from DermNet NZ.
Explore on this siteThe different types of hives (urticaria) The definition of urticaria (hives) and its pronunciation Is it chronic hives or chronic urticaria?
- British Association of Dermatologists. Urticaria pigmentosa. Updated 2015. (accessed 7 Feb 2018).