Primary mast cell disorders in children.

Mastocytosis arises from clonal mast cell expansion and the resultant accumulation of mast cells in cutaneous and sometimes extracutaneous tissues. Recent studies have demonstrated that c-kit mutations seem to be more prevalent in pediatric mastocytosis than previously assumed, but what determines disease evolution and severity in the individual patient remains elusive. For the large majority of children, mastocytosis is a self-limited cutaneous disease that spontaneously regresses before they reach adult age. Rarely, children develop systemic disease progression that is the hallmark of adult-onset disease. Therefore, invasive diagnostic testing, including performing a bone marrow biopsy, is not routinely recommended and usually reserved for children that present with signs of systemic involvement and persistently elevated serum tryptase levels. Despite its often-transient nature and limited skin involvement, some children experience challenging disease-associated symptoms due to spontaneous or trigger-induced mast cell degranulation. Anticipation of and preparation for potential complications can in many instances avoid symptomatic exacerbations. Proper symptomatic treatment and supportive care can often improve the child's quality of life. Cytoreductive therapy is usually not indicated given the natural history of spontaneous disease resolution.