A new study suggests that for some people, a life-threatening allergic reaction to common medications may be the first and only indicator of systemic mastocytosis (SM). Researchers found that nearly 15% of patients in the study initially discovered they had the disease only after experiencing severe drug-induced anaphylaxis.
The retrospective study, published in the journal Medicina, analyzed 34 patients diagnosed with SM between 2009 and 2024. Before conducting allergy tests, the team collected each patient’s medical history, including their specific SM subtype, their baseline laboratory assessments and clinical information on drug hypersensitivity reactions (DHRs). Baseline laboratory assessments included serum tryptase levels (a biomarker measured in the blood to detect mast cell activation), total immunoglobulin E (IgE) concentrations and specific IgE testing for penicillin determinants during stable clinical periods.
The analysis included hypersensitivity reactions to various drug groups, including antibiotics, analgesics, radiocontrast media, anesthetics and COVID-19 vaccines.
The findings showed that 10 out of the 34 patients had a history of drug hypersensitivity. The most common triggers were nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, and beta-lactam antibiotics, like amoxicillin. In both medicine groups, anaphylaxis was the most common reaction, frequently followed by hypotension (low blood pressure). No hypersensitivity reactions occurred to quinolone antibiotics, general anesthetics or COVID-19 vaccines.
In five patients, anaphylaxis was the very first sign of SM. These patients were mostly women, with a median age of 36 and significantly elevated tryptase levels.
Read more about SM signs and symptoms
The researchers found no significant differences in age, sex or tryptase levels between those who had drug allergies and those who did not. On average, participants’ baseline tryptase levels were 50.25 µg/L, more than double the standard 20 µg/L threshold, though results differed significantly between individuals.
Interestingly, some patients displayed a multiple-drug reactor phenotype, experiencing anaphylaxis to various drug classes.
“Careful evaluation of suspected drug reactions, including detailed clinical history, appropriate allergological testing, and identification of safe alternative medications, is essential to optimize patient safety and clinical management,” the authors concluded. They noted that future large-scale studies are needed to better define the clinical characteristics and potential risk factors associated with drug hypersensitivity reactions in patients with SM.
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