Idiopathic mast cell activation syndrome is more often suspected than diagnosed—A prospective real‐life study. Issue 9 (7th April 2022)

• Record Type: Journal Article
• Authors: Buttgereit, Thomas; Gu, Sophie; Carneiro‐Leão, Leonor; Gutsche, Annika; Maurer, Marcus; Siebenhaar, Frank
• Is Part Of: Allergy. Volume 77:Issue 9(2022)
• Page Start: 2794
• Page End: 2802
• Publication Date: 2022-04-07
• Subjects: mast cell activation syndrome -- MCAS -- prospective study -- real‐life -- targeted treatment -- tryptase; Allergy -- Periodicals; 616.97
• DOI: 10.1111/all.15304
• Languages: English
• ISSNs: 0105-4538

Abstract

Abstract: Background: Idiopathic mast cell activation syndrome (MCAS) is characterized by three diagnostic criteria: (1) episodic mast cell (MC)‐driven signs/symptoms of at least two organ systems in the absence of clonal MC expansion and definite triggers, (2) episodic increase in tryptase, and (3) response to MC‐targeted treatment. Many patients believe they have MCAS, but how often this is the case remains unknown. Methods: We prospectively investigated patients with suspected MCAS ( n = 100) for the diagnostic criteria including baseline tryptase, KIT D816V mutation, and patient‐reported outcome measures (PROMs) over the course of 12 weeks. Comorbid depression and anxiety were explored with the Hospital Anxiety and Depression Scale (HADS). Results: In 53% of our patients (80% females), suspicion of MCAS was based on self‐evaluation. In total, patients reported 87 different symptoms, mostly fatigue ( n = 57), musculoskeletal pain/weakness ( n = 49), and abdominal pain ( n = 43), with overall high disease activity and impact. Two of 79 patients had increased tryptase (by >20% +2 ng/ml) following an episode. Only 5%, with any of the PROMs used, showed complete response to MC‐targeted treatment. Depression and anxiety disorders were frequent comorbidities ( n = 23 each), and 65 patients had pathological HADS values, which were linked to high disease impact and poor symptom control. Conclusion: Mast cell activation syndrome was confirmed in only 2% of patients, which implies that it is not MC activation that drives signs and symptoms in most patients with suspected MCAS. There is a high need for comprehensive research efforts aimed at the identification of the true underlying pathomechanism(s) in patients with suspected MCAS. Abstract : A total of 100 patients with suspected idiopathic MCAS were investigated for the diagnostic criteria over the course of 12 weeks. Suspicion of MCAS was frequently based on self‐evaluation. Eighty‐seven different mainly chronic continuous symptoms were reported. Two patients had increased tryptase levels following a symptomatic episode; very few benefited from MC—targeted treatment. Psychiatric morbidity was frequent.Abbreviations: HADS, hospital anxiety and depression scale; MC, mast cell; MCAS, mast cell activation syndrome; QoL, quality of life; PROM, patient‐reported outcome measure