# Anaphylactic Shock Caused by Eating Buckwheat

## TL;DR

A patient experienced severe allergic reactions from eating buckwheat, highlighting the need for better allergen labeling and awareness.

## Contribution

This case report emphasizes the clinical relevance of buckwheat allergy and the diagnostic challenges associated with it.

## Key findings

- Buckwheat allergy can cause severe anaphylactic shocks and requires emergency treatment.
- Diagnosis relies on detailed patient history and specific IgE testing.
- Buckwheat allergen labeling is insufficient in Europe, complicating allergy management.

## Abstract

Background: Urticaria is a common disease with a marked influence on quality of life. The key cell involved is the mast cell, which can be activated by a vast variety of stimuli, and the major mediator is histamine. Allergic urticaria is a disorder with a large variety of causes: food, drugs, insect venom, skin contact with allergens, and physical exercise. Buckwheat consumption has increased in European countries and the USA because it is gluten-free. It can trigger anaphylactic shock if ingested, inhaled, or handled with the hands. Five common buckwheat allergens named Fag e1 to 5 (Fag e1, 2, and 3 are considered the major allergens) and two tartary buckwheat allergens named Fag t1 and Fag t2 have been described. Method: We present the case of a patient who experienced two anaphylactic shocks and in whom the etiological factor was buckwheat. The patient presented to the Allergology department for the evaluation of two episodes of severe allergic reactions that required emergency therapy, episodes that involved the loss of consciousness and were of major severity. At each anaphylactic shock, an ambulance was requested, and emergency therapy was administered, leading to the patient’s recovery within a few hours. Diagnosis: Since each episode occurred a few minutes after eating, the diagnosis was established based on a detailed anamnesis and prick skin tests, followed by specific IgE dosages. Other foods consumed by the patient, assessed by prick skin testing and specific IgE dosages of suspected foods, were excluded as the etiological cause. Increased levels of buckwheat-specific immunoglobulin E were highlighted, thus identifying the etiological agent. The treatment of anaphylactic shock was performed urgently by the ambulance crew with adrenaline, infusion solutions, cortisone preparations, and antihistamines. Result: Following the treatment that was initiated, there was a partial remission of the lesions after a few hours. Conclusions: Buckwheat allergy is rare, but it produces symptoms that affect the skin, gastrointestinal tract, and respiratory tract, as well as anaphylaxis. In a professional environment, it can trigger allergic rhinitis, asthma, and hives. Although buckwheat allergens have been described, their clinical relevance has only been studied in a small number cases. In current practice, the only commercially available allergen is Beech e2 per the ImmunoCAP ISAC microarray. Diagnosis can be difficult in clinical practice. This reported case suggests the need for a thorough anamnesis, since buckwheat is consumed as a hidden allergen, and in Europe, it is not necessary to label foods containing this allergen.