Mastocytosis is a rare condition in which too many mast cells swell in the body’s tissues. Mast cells are a type of white blood cell which is part of the immune function in the body. These cells are responsible for releasing chemicals that create inflammatory responses.


According to the National Institutes of Health (NIH), there are two forms of mastocytosis:


Cutaneous mastocytosis, which only affects the skin, and is seen most commonly in children. Systemic mastocytosis, which affects other parts of the body, and is more common in adults. This type of mastocytosis is a fatal blood disease with no known cure. Since mastocytosis can affect different parts of the body, signs, and symptoms may vary. The following symptoms may appear in a person with mastocytosis.

1. Skin discoloration

The most common manifestation of cutaneous mastocytosis is tan-red macules (discolored areas of skin) which most often appear on the arms, legs, and abdomen.


In young children with cutaneous mastocytosis, the symptoms usually resolve by puberty.