D3.480 - Protamine Hypersensitivity Risk in an Elderly Patient with Recurrent Food Anaphylaxis and High Cardiovascular Risk- Case Report

The diagnosis of food-induced anaphylaxis, in addition to identifying the triggeringagent, requires assessment of the risk of potential cross-reactive reactions. Anessential component of the diagnostic work-up is the evaluation of baseline serummast cell tryptase levels.

The diagnosis of food-induced anaphylaxis requires not only identification of thetrigger but also assessment of the risk of cross-reactivity. Baseline serum mast celltryptase (sBT) measurement is an essential part of the work-up.

A 74-year-old man with severe cardiovascular comorbidities (ischemic heart disease,history of NSTEMI, atrial fibrillation, peripheral arterial disease) was admitted forevaluation of recurrent anaphylaxis (Ring and Messmer grade II). Episodes occurredafter metamizole intake, consumption of squid and salmon, and various foodspreceded by alcohol. No hypersensitivity to other drugs, including aspirin orperioperative agents, was reported. Total IgE was 129 IU/L; multiplex ALEX assayrevealed sIgE to rAra h 9 was 0,32 kUA/L (class 1), with no other sensitizations,including salmon (rSal s 1 was <0,10 kUA/L) and shellfish. Baseline sBT waselevated (18 ng/mL and 15.8 µg/L). No KIT D816V mutation or aberrant expression ofCD25/CD2 on mast cells was detected.Given the potential use of protamine during angiography and theoretical cross-reactivity with fish proteins, hypersensitivity testing was performed. Skin prick andintradermal tests were negative; however, the basophil activation test (BAT) waspositive. A heparin-free procedural protocol was recommended. The patient wasdiagnosed with idiopathic mast cell activation syndrome (MCAS); clonal MCAS withmutations other than KIT D816V could not be excluded.

This case highlights the complexity of managing recurrent food-induced anaphylaxisin elderly patients with severe cardiovascular disease. Elevated baseline sBT mayreflect either MCAS or systemic comorbidities, such as advanced atherosclerosis.Careful evaluation of cross-reactivity risk and individualized procedural protocols,including BAT-guided assessment, are crucial for patient safety.