Advanced systemic mastocytosis – an underestimated disease
Published online: May 14, 2020
Systemic mastocytosis (SM) is a rare hematologic disease with a broad spectrum of clinical symptoms related to mast cell degranulation (e.g. diarrhea, allergic reactions, pruritus etc.). SM can be subdivided into indolent SM, mainly characterized by symptoms without impact on survival and advanced SM (advSM), the worst form of SM associated with reduced life expectancy due to severe organ infiltration and dysfunction. As the symptoms are diverse and the level of awareness is rather low, underdiagnosis or misdiagnosis is a common problem especially in patients with advSM.
The study by Schwaab et al. recently published in The Journal of Allergy and Clinical Immunology: In Practice therefore analyzed the frequency of this underestimated disease in Germany and looked for essential parameters for correct diagnosis of advSM and especially for distinction between indolent SM and advSM.
Approximately 0.8 newly diagnosed patients with advSM per 1 million inhabitants get diagnosed with this disease per year in Germany, leading to approximately 500 patients currently being treated in Germany. In around 1/3 of the analyzed patients, misdiagnosis led to a delay in therapy, possibly resulting in inferior outcome in terms of survival. Analysis of serum tryptase levels and knowledge of mutation status in peripheral blood, as well as a thorough analysis of the bone marrow by a specialized pathologist, and consultation of a specialized hematologist in the diagnostic work up are parameters that facilitated a correct diagnosis of advSM.
The authors suggest that with rising disease awareness and standardized diagnostic steps, incidence and prevalence of advSM will rise. The above-mentioned diagnostic steps should therefore be used in patients with suspected SM, especially in those with suspected advSM. The correct diagnosis of advSM and discrimination between advSM and indolent SM is of utmost importance, since with availability of targeted treatments, the therapeutic landscape and hence the outcome of patients with advSM, has improved significantly over the last few years.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.