OR WAIT null SECS
Indolent Systemic Mastocytosis’ Diagnostic Clues, with Patricia Lugar, MD
HCPLive spoke with Lugar on indolent systemic mastocytosis’ allergic manifestations and diagnostic markers.
This past fall on November 21, 2024, Patricia Lugar, MD, from the Duke Asthma, Allergy, and Airway Center, participated in the workshop, “Best Practices in Managing Indolent Systemic Mastocytosis (ISM),” hosted by OncologyLive and HCPLive. During this event, Lugar emphasized several key points regarding the diagnosis and management of ISM, such as diagnostic challenges, the importance of serum tryptase testing, overlooked conditions, and symptom management.
HCPLive spoke with Lugar several months after the workshop, hoping to deepen the discussion on ISM. Lugar discussed several ISM topics—allergic manifestations, patterns of anaphylaxis, and diagnostic markers or tests.
“Allergic reactions in patients with mast cell disorders are oftentimes one of the clues that tell us this patient may have a mast cell disease,” Lugar said.
Although anyone can have an allergic reaction to bees, hornets, and wasps, people with a mast cell disease have slightly different reactions. It is common for patients with a mast cell disease to have predominantly cutaneous systems. For instance, 70 to 80% of patients will have flushing or may experience blotchiness in their skin or itchiness that can progress to a visible rash.
“That's one of the key questions we always ask patients about,” Lugar said. “What did your skin look like? Did someone see a rash?”
A patient who may experience suspected anaphylaxis following a venom sting could potentially have syncope, feeling lightheaded and a sense of doom.
“It's as if they go directly into anaphylaxis within a few short minutes,” Lugar said. “When patients are describing this, take a look at the record to see well, did you have any cutaneous symptoms? Because in general, that would be quite unusual for someone not to have cutaneous symptoms, but in mast cell disorders, it's quite common for folks to have syncope, lightheadedness, shortness of breath, tachycardia, some cardiopulmonary symptoms without the warning of a cutaneous set of symptoms and without tracking that to help clinicians think that this is anaphylaxis.”
The most common triggers for ISM include venom stings or food (i.e. shellfish). Other triggers could include exercise, heat exposure, and the environment.
Lugar recommends patients with a suspected mast cell disorder to undergo serum tryptase testing. The testing could have limitations, however.
Clinicians may rely on signficantly elevated tryptase levels to diagnose mast cell disorders, but patients with clonal mast cell disorders may have tryptase levels in the mid-range (8 – 11), which can be overlooked. Physicians unfamiliar with these cases may not investigate further if the tryptase is < 20, potentially missing a diagnosis despite clinical symptoms.
“The limitations to tryptase are that we don't know how to use tryptase as a universal marker, where we can tell folks: ‘if it is above this level, this is the probability that you need to investigate with a bone marrow examination,’” Lugar said. “[Serum tryptase testing is] a cornerstone to our steps of evaluation. As an allergist [and] immunologist, limitations are not knowing what a good cutoff is universally.”
For more insights on diagnosing indolent systemic mastocytosis as well as to learn more about managing indolent systemic mastocytosis, read Best Practices in Managing Indolent Systemic Mastocytosis (ISM): Disease Mechanisms, Diagnostic Challenges, and Multidisciplinary Treatment Strategies here.
Relevant disclosures for Lugar include Blueprint Medicines Corporation, Grifols USA, BioCryst US Scales, and Grifols Shared Services North America.
References
