Genuine awareness of mammalian meat such as beef and pork: Myth or reality?

Abstract

Background: Genuine sensitization to beef and pork is rare, with the best-characterized allergens being beef and pork (Bos d 6 and Sus s1). There are different presentations of mammalian meat allergy: cat-pork syndrome, alpha-gal syndrome, milk-related allergy, and primary sensitization.

Case report: A 49-year-old man presented with urticaria after ingesting beef and pork and mild intermittent nasal symptoms. The initial approach was aeroallergen testing: positive for cat. Cat-pork syndrome was suspected. A prick-to-prick test was performed on raw and cooked pork: positive; raw beef: positive; cooked beef: indeterminate; oral examination was performed: positive; 40 minutes later, wheal-like lesions were present on the neck, anterior thorax, and face. Fel d 1 (0.92 kcal/L) and Fel d 2 (0.05 kcal/L) were ordered, confirming genuine cat sensitization and ruling out cat-pig syndrome. Specific IgE to pork (0.18 kcal/L), confirming sensitization to pork. Given the presence of symptoms associated with beef and the likelihood of α-Gal syndrome, skin and intradermal polygeline testing was performed: negative. Bos d4 (0.02 kcal/L) and Bos d5 (0.01 kcal/L) were negative, confirming primary sensitization to beef.

Conclusion: After ruling out other mechanisms, primary sensitization to mammalian meat is presumed. A molecular approach can improve diagnostic accuracy and guide therapeutic decision-making in this case: Total avoidance.

Keywords: Cross-reactivity; Type 1 hypersensitivity; Cat-pig syndrome; Alpha-Gal syndrome; Food hypersensitivity.