Ep. 126: Management of mast cell activation syndrome - A clinical yardstick
Part of the series: The Itch Review
LISTEN TO EPISODE 126: Apple Podcast • Spotify • Amazon Music
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Mast cell activation syndrome (MCAS) is a confusing and often misunderstood condition. If you’ve ever wondered about MCAS symptoms, serum tryptase testing, or how treatments like antihistamines, sodium cromolyn, and even omalizumab fit in, this episode is here to help.
We review the findings from “Management of indolent mastocytosis and mast cell activation syndrome - A clinical yardstick,” published in June 2025 in The Annals of Allergy, Asthma & Immunology. Because the paper covers both diseases, we’ve split it into two parts. This episode focuses on mast cell activation syndrome (MCAS).
What we cover in our episode about mast cell activation syndrome:
Yardsticks explained: Why the ACAAI uses yardsticks as practical, interim guidelines before full consensus statements are available.
Classifying mast cell disorders: Primary (clonal), secondary (allergy/autoimmune), and idiopathic (MCAS).
MCAS diagnosis criteria: Symptoms in 2 or more organ systems, objective evidence (serum tryptase or urinary metabolites tests), and positive response to therapy.
Treatment strategies: Include trigger avoidance, H1/H2 antihistamines, leukotriene blockers, mast cell stabilizers (such as cromolyn and aspirin), off-label biologics like omalizumab, and epinephrine.
Neuropsychiatric symptoms: Brain fog, anxiety, and depression are common and require multidisciplinary management.
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Ep. 121: Avapritinib vs Placebo in Indolent Systemic Mastocytosis - PIONEER Trial
Ep. 118: The ISM Disconnect - Do Patients and Providers Agree on Symptom Control?
Ep. 70 How do stress and low histamine diets impact mast cell disease?
Ep. 63: Mast Cell Diseases & Systemic Mastocytosis: The Basic Science
Watch more episodes about mast cell disease
The Itch Review, hosted by Dr. Gupta, Kortney, and Dr. Blaiss, explores allergy and immunology studies, breaking down complex research in conversations accessible to clinicians, patients, and caregivers. Each episode provides key insights from journal articles and includes a one-page infographic in the show notes for easy reference.
Timestamps
Our episode discusses the diagnosis and treatment of mast cell disease in the yardstick from 2025
01:21 What is a yardstick?
02:59 How mast cell disorders are classified
06:28 Diagnosing mast cell activation syndrome (MCAS)
08:15 Criteria 1: Symptoms in 2+ organ systems
10:25 Criteria 2: Tryptase and other lab tests
15:05 Criteria 3: Treatment response
16:38 Why diagnosis is still complex
20:11 Trigger avoidance strategies
21:56 Antihistamines: H1 and H2 blockers
25:29 Add-on therapies: leukotriene blockers
26:24 Cromolyn and aspirin
28:16 Managing brain fog and mental health
29:31 When to prescribe epinephrine
32:51 Omalizumab in MCAS
35:29 Final takeaways from the doctors
