Anaphylaxis Due To Buckwheat Skin Testing

Abstract

INTRODUCTION: Buckwheat is a common crop in Asia, Europe and USA. Like peanut, buckwheat allergy can be fatal. To our knowledge, while anaphylaxis after skin testing with nuts is not exceptional, there has been no report of such with buckwheat. We report herein the first case. CASE HISTORY: A 26 year-old Chinese female presented to the Emergency Department with pruritic wheals, dyspnoea and hoarseness 15 minutes after eating Japanese buckwheat noodles. On examination, she had a swollen uvula, periorbital swelling, and generalised urticaria. Prompt recovery followed epinephrine, steroids and antihistamine administration. A referral to our service was made. She reported 2 previous episodes of similar reactions. Once after eating a sandwich containing olives, another after a muesli bar with avocadoes. Both were likely to have contained buckwheat. Skin prick tests (Greers) to peanuts, tree nuts, fish, shrimps, crabs, mussels, clams, scallops, oyster, milk, soy, and wheat were negative. On another occasion, skin prick tests to commercial buckwheat allergen (ALK); and prick-by-prick with raw and cooked buckwheat extract, olives and avocadoes were performed. All the buckwheat tests resulted in positive reactions with the largest wheal being 14mm x 9mm. During this session, she developed anaphylaxis evidenced by flushing and dyspnoea. Peak expiratory flow rates improved from 300 to 370 after epinephrine, antihistamine and steroid administration. Subsequent open-food challenges to avocadoes and olives were negative, confirming buckwheat as the allergen causing anaphylaxis after skin testing. CONCLUSION: In patients at risk of anaphylaxis, it is advisable to use only diluted commercial buckwheat extract for skin testing with resuscitative equipment readily available.