Generic term for clinically heterogeneous clinical pictures characterized by mast cell hyperplasia in the skin (and in internal organs). The spectrum ranges from solitary skin tumors to variously pronounced (variants of the so-called"urticaria pigmentosa"), in extreme cases erythrodermic skin manifestations.
The term "cutaneous mastocytosis" implies a purely cutaneous clinical picture. This is mostly found in children, less frequently in adults. Adult forms of mastocytosis are usually a "systemic disease" with a differently accentuated extracutaneous pattern of infestation, in which the cutaneous infestation can be regarded as a monitory and thus frequently leading to a diagnosis.
Tryptase: If systemic mastocytosis is suspected, tryptase is determined according to the guidelines (standard value: <20µg/l). If the value is exceeded, systemic mastocytosis is considered possible and a bone marrow biopsy and screening for other systemic involvement is sought. At low levels, extensive diagnostic testing is usually not performed without compelling clinical evidence. In a larger study, systemic mastocytosis could be confirmed in 32% of patients with cutaneous mastocytosis by bone marrow histology. In addition, N-methylhistamine or 1,4-methylimidazole acetic acid can be determined in the collected urine.