SYSTEMIC MASTOCYTOSIS WITH CONCURRENT ALPHA-GAL ASSOCIATED ANAPHYLAXIS

Abstract

<h3>Introduction</h3> We present a case of a patient, diagnosed with systemic mastocytosis (SM), who was also found to have anaphylaxis to galactose-α-1,3-galactose (alpha-gal) several years after his initial SM diagnosis. <h3>Case Description</h3> The patient initially presented in his 20s with recurrent episodes of hypotension, pre-syncope, and syncope. An extensive cardiac and neurologic workup did not elucidate an etiology. He moved to Mississippi and had a six-year period with no episodes. In 2015, he was admitted to the intensive care unit due to presumed septic shock secondary to an infected pilonidal cyst. A tryptase level during hospitalization was elevated at >30, and a bone marrow biopsy confirmed the diagnosis of indolent SM. After starting antihistamines, the patient was initially free of anaphylaxis episodes. The patient then began experiencing weekly anaphylactic episodes, often with severe hypotension, sometimes requiring multiple doses of epinephrine. Episodes persisted despite increased antihistamine regimen. After extensive testing, he was found to have elevated alpha-gal specific IgE and was diagnosed with alpha-gal-associated anaphylaxis. With mammalian meat avoidance, he had no further anaphylactic episodes. <h3>Discussion</h3> Our reports highlight the importance of considering food allergens, particularly alpha-gal, in locations with a high incidence of lone star tick bites, as possible triggers for recurrent anaphylaxis in patients with SM. Given the delayed presentation of alpha-gal reactions and the inherent propensity for patients with SM to experience anaphylaxis, this diagnosis can easily be overlooked. The case also suggests the possibility that underlying SM may be associated with more severe manifestations of alpha-gal reaction.