Progression of Food Allergy from Gastrointestinal Symptoms to Potential Anaphylaxis

Case at a Glance

A 32-year-old female epidemiologist with a known shellfish allergy presenting with worsening gastrointestinal symptoms, including hematemesis for the first time, following accidental shellfish ingestion.

Patient's Story

The patient has a documented history of shellfish allergy that developed during her teenage years. She typically experiences severe vomiting 2-3 hours after shellfish ingestion and maintains strict avoidance. Recently, she had an accidental exposure that resulted in prolonged severe vomiting with hematemesis - a new symptom not experienced in her previous 4 documented exposures over her lifetime. Despite immediate self-treatment with ondansetron 8mg ODT and diphenhydramine 50mg upon recognizing the exposure, her symptoms persisted and required emergency department intervention.

Initial Assessment

The patient presented to the emergency department with severe vomiting and hematemesis following accidental shellfish ingestion. Her symptoms were refractory to initial home treatment with antiemetics and antihistamines. She reported no accompanying diarrhea, skin manifestations, or respiratory symptoms during this or previous episodes.

The Diagnostic Journey

Given the patient's history of shellfish allergy and the new presentation of hematemesis, the emergency physician evaluated for potential progression of her allergic response. The delayed onset (2-3 hours post-ingestion) and purely gastrointestinal presentation were consistent with her historical pattern, but the bleeding component represented symptom escalation.

Final Diagnosis

Shellfish allergy with severe gastrointestinal manifestations and evidence of symptom progression (new hematemesis)

Treatment Plan

Emergency department treatment included IV droperidol for antiemetic effect, pantoprazole for gastric protection given the hematemesis, and diphenhydramine for antihistamine coverage. The patient was prescribed an epinephrine auto-injector for future use given the potential for progression to systemic anaphylaxis. Enhanced allergen avoidance strategies were reinforced.

Outcome and Follow-up

The patient's acute symptoms resolved with treatment. She was counseled on the risk of repeated exposures potentially leading to more severe reactions, including respiratory involvement. The consulting physician noted that while specific data on progression rates from isolated GI symptoms to systemic anaphylaxis is limited in the literature, repeated exposure remains a known risk factor for anaphylaxis severity. The patient was advised to continue strict avoidance measures and carry the prescribed epinephrine auto-injector.