D1.179 - Cruciferous Vegetables and Food Allergy: A Case Study on Steamed Broccoli-Induced Urticaria

Allergies to cruciferous vegetables, such as broccoli, are rare but can manifest with severe symptoms, especially in pediatric patients. The allergenicity of these vegetables is influenced by cooking methods, which may alter the protein structure and IgE reactivity. This study investigates a case of urticaria triggered by steamed broccoli

A 4-year-old girl developed a pruritic urticarial rash on her lower extremities that spread systemically within 10 minutes of consuming steamed broccoli alongside breaded frozen hake. The patient had a history of allergic reactions to peach with skin, kiwi, and banana, but tolerates peach without skin and other common allergens. Skin prick tests revealed sensitization to kiwi, banana, and peach skin, as well as a positive response to steamed broccoli.

Protein extracts were prepared from raw and cooked broccoli, cauliflower, and cabbage. SDS-PAGE and Western blot analyses were conducted to identify protein profiles and evaluate IgE reactivity using the patient’s serum.

Western blot analysis showed IgE binding to proteins ranging from 20–150 kDa in all raw cruciferous extracts, with reduced binding in cooked samples, except for steamed broccoli. Proteins in steamed broccoli retained sufficient allergenicity to elicit a reaction, indicating partial resistance to thermal denaturation

This case highlights the allergenic potential of steamed broccoli and the role of thermal processing in modulating protein allergenicity in cruciferous vegetables. Detailed allergenic profiling of these foods is essential for accurate diagnosis and dietary recommendations. Further research is needed to elucidate the specific proteins responsible for these reactions and their thermal stability.