Meat allergy

Meat allergy is a diverse disease with symptoms reaching from local contact reactions to severe anaphylaxis. It may start early in life or manifest only in late adulthood. Immunologically, meat allergies may represent true food allergies or may develop in patients sensitized to airborne serum albumins from cat/dog dander or bird feathers due to the presence of cross-reacting serum albumins in meat (cat-pork-syndrome, bird-egg-syndrome). Likewise, sensitization to bovine serum albumin in milk-allergic children may be associated with beef intolerance. Overall, meat allergens are still poorly characterized with only three being currently listed by the IUIS (Gal d 5: chicken serum albumin/egg yolk alpha-livetin, Bos d 6: bovine serum albumin, Bos d 7: bovine IgG). Immunoglobulin G represents another major allergen in red meat, especially in adults. Like serum albumins, IgG is considered heat-labile. In genuine meat allergies, several low-molecular weight proteins between 5 kDa and 25 kDa have been identified in poultry and in red meat as partly muscle-specific and heat-resistant allergens (e.g. myoglobin, alpha-parvalbumin, hemoglobin). Very recently, delayed anaphylactic reactions after the consumption of red meat have been reported in subjects with IgE antibodies against alpha-galactose, a highly immunogenic carbohydrate structure present in all mammals with the exception of old-world monkeys and humans. Diagnosis of a meat allergy by skin testing and IgE determination using commercially available non-standardized meat extracts is hampered by low sensitivity. On the other hand, positive test results with low clinical relevance may be commonly encountered in subjects sensitized to heat-labile meat allergens such as serum albumins.