Skin problem. This is a skin disorder. I recommend asking a dermatologist this question.
Not much. Mastocytosis of the skin is common in children and is ususally resolved by or before the teenage years. In adults, it may or may not ever resolve. Mastocytosis throughout the body (systemic mastocytosis) will most likely never go away, but luckily is not life-threatening. In rare cases where the systemic mastocytosis is associated with leukemia, chemotherapy may help. See a specialist for info.