Abstract and Introduction
Abstract
Introduction: Delayed allergy to red meat, also termed alpha-gal syndrome, is increasingly reported in adults and African communities, while pediatric cases remain rare.
Case Presentation: Here, we report on a 7-year-old Caucasian boy presenting with recurrent wheals since the age of 5 years old. Episodes with hives occurred around every 3 weeks, mainly in the evening. One of these episodes was also associated with angioedema. No clear trigger was identified. At the first visit, after excluding an infection and autoimmune thyroiditis, chronic spontaneous urticaria was suspected and symptomatic treatment with antihistamines was prescribed. Six months later, the boy presented at the emergency room with generalized urticaria, dyspnoea, and emesis. Symptoms resolved after administration of epinephrine and antihistamines. A detailed medical history after this event revealed that he had eaten three sausages as well as jelly beans containing gelatine several hours prior to this episode. More precisely, after eating the sausages and jelly beans during the day, he had shown some hives before going to bed, and later developed the other symptoms in the middle of the night, suggesting alpha-gal syndrome. In his history, several tick bites are reported. Immunoglobulin E levels for alpha-gal were clearly elevated, confirming the diagnosis of a delayed-appearing immunoglobulin E-mediated allergic reaction to alpha-gal. Emergency medication was prescribed and avoidance of red meat and gelatine-containing foods was recommended. Under this exclusion diet, the boy remained asymptomatic, with the exception of two accidents in the follow up of 3 years, one developing during a barbecue and the second after exceptionally eating marshmallows.
Conclusion: A detailed clinical history led to the diagnosis of alpha-gal syndrome. Although alpha-gal syndrome is typically seen in adults, our case illustrates that children can also present with this potentially life-threatening allergy. Since alpha-gal syndrome is rare in Europe, the disease is not well known and often overlooked for several years, especially in children.
Introduction
Galactose-alpha-1,3-galactose (alpha-gal) has recently been identified as a novel food allergen, with a first description in 2008 when immunoglobulin (Ig)E to alpha-gal was identified.[1] Typically, alpha-gal-containing foods, such as red meat and gelatine, are associated with delayed anaphylaxis in sensitized patients, 2–6 hours after ingestion. Symptoms can include urticaria, angioedema, respiratory distress, gastrointestinal symptoms (cramping, nausea, emesis), and also syncope without any other clinical manifestations. Due to the temporal delay of the symptoms, the diagnosis often remains challenging. A detailed medical history may help to identify the allergen and direct the appropriate exclusion diet. Interestingly, this allergen is a carbohydrate expressed in different tissues and cells of mammalians, except in primates. Therefore, the avoidance of red meat and its derivatives (including gelatine-containing sweets) is the mainstay of treatment.
Furthermore, tick bites have been related to the development of this food allergy. In Europe, the most frequent tick is Ixodes ricinus and, as in other types of ticks, alpha-gal has been identified in the gut of these ticks.[2] There are three hypotheses that attempt to explain the relationship between tick bites and alpha-gal syndrome by suggesting the tick bite contribute to sensitization: (1) presence of alpha-gal in the saliva of the ticks; (2) presence of mammalian blood from previous bite(s) in the saliva of the ticks; and (3) presence of commensal bacteria expressing alpha-gal, such as Borrelia burgdorferi, in the saliva of the ticks.[1]
The incidence rates of this allergy are not yet clear, and only few pediatric cases have been described (Table 1), especially in the USA, where meat allergy in general is more frequent.[3,4] There is only one case series that also describes a pediatric case in Europe.[5] In addition, in a large study on the prevalence of alpha-gal sensitization in Germany, including 107 children out of a total of 1369 patients, the authors did not find a confirmed pediatric alpha-gal syndrome with clinical symptoms, despite a similar prevalence of alpha-gal sensitization between adults and children.[6] With this case report, we want to raise awareness in populations with a low incidence of alpha-gal syndrome, especially in children, where the exposure risk to gelatine-containing sweets might be different than in adults.
J Med Case Reports. 2023;17(6) © 2023 BioMed Central, Ltd.
