What is alpha-gal allergy and how is it linked to red meat allergy?

Alpha-gal allergy is a syndrome that was first described in 2009 as a delayed anaphylaxis to red meat, specifically an excessive IgE antibody response to an oligosaccharide epitope, galactose-alpha-1,3-galactose. This reaction typically occurs about three to eight hours after eating red meat. As with other food allergies, the prominent symptoms can include severe itching and hives and in severe cases may lead to anaphylaxis (an extreme allergic reaction with symptoms such as tongue or throat swelling and vomiting) which can be fatal without proper medical attention. Source: https://www.columbia-lyme.org/alpha-gal-meat-allergy.