Amblyomma americanum mammalian meat and meat products. The allergy manifests as anaphylaxis — a life-threatening allergic reaction characterized by constriction of airways and a drop in blood pressure. This response is triggered by an IgE antibody to the mammalian oligosaccharide galactose-alpha-1,3-galactose (alpha-gal). As well as occurring in non-primate mammals, alpha-gal is also found in cat dander and in the drug cetuximab. Allergic reactions to alpha-gal usually occur 3–6 hours after consuming red meat, unlike allergic reactions to other foods, whose onset following consumption is more or less immediate, making it more difficult to identify what caused the reaction. Skin tests with standard
Allergic transfusion reaction Allergic transfusion reaction An allergic transfusion reaction is a blood transfusion that results in allergic reaction. It is among the most common transfusion reactions to occur. Reported rates depend on the degree of active surveillance versus passing reporting to the blood bank. Overall, they are estimated to complicate up to 3% of all transfusions. The incidence of allergic transfusion reactions is associated with the amount of plasma in the product. More than 90% of these reactions occur during transfusion. Allergic reactions from blood transfusion may occur from the presence of allergy-causing antigens within the donor's blood, or transfusion of antibodies