No Bull: A Case of Alpha-Gal Syndrome Associated With Buffalo Meat Sensitivity.

Introduction: Alpha (⍺)-gal syndrome (AGS) is an immunoglobulin E (IgE) antibody response against the glycoprotein carbohydrate galactose-⍺-1,3-galactose-β-1-(3)4-N-acetylglucosamine-R (Gal⍺-1,3Galβ1-(3)4GlcNAc-R or ⍺-gal) that is present in Ixodida (tick) saliva and noncatarrhine mammals as well as cetuximab, antivenom, and the zoster vaccine. The most frequently observed anaphylactic reactions in AGS are observed after beef, pork, lamb, and deer meat consumption. We present the first case of anaphylaxis to buffalo meat.

Case report: A 55-year-old man presented with a history of recurrent urticaria that only developed approximately 7 hours after buffalo consumption. The patient denied history of Ixodidae bites but admitted to frequent hiking outdoors. Anti-⍺-1,3-gal IgE was positive (30.80 kU/L). The patient was advised to strictly avoid red meat.

Discussion: The prevalence of AGS has been increased in all continents in the past decade, and several Ixodidae species have been associated with this hypersensitivity. The list of IgE-mediated reactions to various types of meat has expanded to kangaroo, whale, seal, and crocodile, although these have not been associated with AGS. van Nunen only cautioned against consumption of exotic meats, such as buffalo, but no published case report describes AGS associated with anaphylaxis to this type of meat.

Conclusion: AGS is a mammalian meat allergy that has been increasingly prevalent worldwide, especially in Ixodidae endemic regions of Australia and the United States. Multiple AGS case reports published in the past decade demonstrate rapidly increasing understanding of underlying mechanisms provoking ongoing sensitization to help devise management strategies and dietary information. We offer the first case report of delayed anaphylaxis to buffalo meat.