D1.283 - Idiopathic anaphylaxis in a child, Alpha-gal syndrome. Is it an entity in children?

Introduction: Idiopathic anaphylaxis is infrequent in children, accounting for 10% anaphylaxis cases.

Case Report: We present the case of a 10-year-old male with no significant prior medical history, referred to our department for evaluation due to an anaphylaxis reaction occurring seconds after a meal. Immediately after consuming a meal consisting of salad (tomato, onion, and olives), soup and rabbit meat with almonds, the patient developed cervical pruritus, maculopapular erythema, and dyspnea with lack of oral and digestive symptoms. He required urgent care at a nearby hospital, where he was treated with adrenaline, corticosteroids and dexchlorpheniramine, leading to rapid symptom improvement.

Skin prick tests using a panel of common inhalant and food extracts, including nuts and rabbit meat, yielded negative results. Total and specific IgE measurements (almond and rabbit meat) were also negative. Initially, the anaphylaxis was considered idiopathic, prompting an expansion of laboratory tests to include other IgE determinations in a singleplex platform (alpha-gal, beef, pork, mutton, milk, and nFel d 2) and in a multiplex platform. Among these, only alpha-gal-specific IgE tested positive (2.45 kU/L). The multiplex assay revealed positive but clinically irrelevant results to aeroallergens.

Further history taking revealed the patient had eaten a pork belly sandwich 4 hours before the onset of symptoms and engaged in physical activity shortly thereafter. Additionally, the patient frequently experienced tick bites. Despite this episode, he reported tolerance of meat on subsequent occasions.

Conclusions: We report a case of delayed anaphylaxis triggered by pork in a 10-year-old child, posing as an idiopathic anaphylaxis. Foods are the most frequent elicitors in childhood anaphylaxis, with short time intervals between exposure and symptoms´ onset. Initial work-up was consistent with such data. A negative allergy work-up lead to expanded analysis and a clinical story, revealing the exposure to meats and cofactors.

Alpha-gal syndrome is exceedingly rare in pediatric patients, with only a few cases reported in the literature. Management recommendations for children mirror those for adults, emphasizing education on alpha-gal´s role as a hidden allergen in foods, medications, and medical treatments, the importance of cofactors (physical activity for children Vs alcohol in adults) and epinephrine use.