C32-02 A Novel Presentation of Food-dependent Exercise-induced Anaphylaxis

Abstract Introduction Food-dependent exercise-induced anaphylaxis (FDEIA) is a rare phenomenon (lifetime prevalence 0.05%) in which the combination of food that is normally well-tolerated and rigorous exercise causes an anaphylactic reaction. These reactions generally manifest as urticaria, nausea, and angioedema, but may progress to anaphylactic shock in severe cases. In this case, we describe a case of FDEIA whose presentation also included melena/hematochezia. Case A 24 year-old female with past medical history only significant for lactose intolerance was brought into the Emergency Department after losing consciousness. She had reportedly visited Philadelphia from a foreign country and experienced abdominal bloating after a “heavy” dinner consisting of bread and shellfish. Two to three hours later, she went for a run outside her hotel and developed lightheadedness and lost consciousness. She denied consuming dairy or alcohol and otherwise has no known allergies. On arrival, she was somnolent, tachycardic, and hypotensive to 58/30mmHg. She also had melanotic stools that transitioned to bright red blood per rectum as well as a diffuse erythematous rash and edema in all four extremities. Labs were significant for normal erythrocyte sedimentation rate and C-reactive protein, negative infectious stool panel, elevated IgE level at 288 and severe lactic acidosis. She was admitted to the Medical Intensive Care Unit (MICU) for metabolic acidosis and electrolyte derangements. She was treated with intravenous methylprednisolone and fluids. She underwent an esophagogastroduodenoscopy which revealed several non-bleeding gastric erosions. She also underwent transthoracic echocardiogram for syncope work-up, which was normal. Her symptoms briskly resolved and she was discharged on a proton-pump inhibitor. Discussion This case is the first in the current literature that describes gastrointestinal bleeding as a potential downstream effect of FDEIA. Potential triggers for this patient include wheat and shellfish, which is consistent with previously documented cases. The pathophysiology behind FDEIA is still incompletely understood, but several mechanisms are proposed to account for the delayed onset of symptoms. These include increased gastrointestinal vascular permeability leading to increased contact between allergens and gut mast cells and basophils, as well as blood flow redistribution to the intestines during exercise. As a result of these aforementioned mechanisms, we propose that our patient experienced an IgE-mediated, Type I hypersensitivity reaction leading mast cell-mediated disruption of the mucosal barrier and subsequent causation or exacerbation of gastric erosions and ultimately, gastrointestinal bleeding. This abstract is funded by: None