A hidden food allergen : soy

Soy products are widely used in a variety of processed foods such as meet products, sausages, chocolate and breakfast cereals. The prevalence of soy allergy in adults is unknown. The development of soy allergy in the late adulthood is rare. In adults soy allergy mostly presents either as an occupational allergy or pollen-food syndrome developed on the ground of birch sensitization. A 38-year-old female referred to Allergy Unit with a history of oral allergy syndrome (OAS), itching of the scalp and palms, generalized urticaria, rhinitis and dyspnea necessitating intervention in the emergency department in few minutes after ingestion of meat with sauce or meatball at the restaurant for ten years. She also reported to experience OAS after ingesting ready soup, chocolate, pastry and cookies. The personal history did not reveal allergic rhinitis, asthma, atopic dermatitis, drug or venom allergy. The repeated SPTs with soy revealed a remarkable wheal which is greater than the positive control. The SPT with aeroallargens including birch was found to be negative. The soy-specific IgE was noticeably positive (82.30 IU/L). We described herein an adult patient presented anaphylaxis upon ingestion of soy-containing foods in the absence of a triggering factor such as exercise, previous food allergy history, aeroallergen sensitization including birch and occupational soy exposure that make this case as unique.