I first heard of the scarcely-known condition known as mammalian meat allergy, which can cause deadly anaphylaxis, a few years ago, but it is of growing concern. It can result from a bite from a lone star tick, whose range is expanding to include the entire Eastern seaboard and large parts of the midwest, thanks to climate change. (See this CDC map.) Lone star ticks are big for a tick, crawl quickly, and their bites hurt, in contrast to the smaller tick that transmits Lyme disease. And their bites are on the rise.
Some antigen introduced by the Lone star tick bite triggers the immune system to attack a compound called galactose-alpha-1,3-galactose, or alpha-gal for short, which is found in red meat derived from any non-primate mammalian species as well as pork. Affected individuals sometimes but not consistently develop allergy symptoms 3-8 hrs after meat consumption, which can range from GI cramping and diarrhea, through classical allergic symptoms like itching and swelling, but potentially all the way up to life-threatening anaphylaxis with cardiovascular collapse, airway swelling and respiratory compromise. People often remember receiving a painful tick bite before the initial development of their allergy.
The presence of an alpha-gal allergy can be established with a blood assay for the relevant antibodies. If you think you have alpha-gal allergy, consult a physician, obtain the appropriate testing, get a prescription for an epi-pen, and (probably) stop eating red meat. While mammalian meat is the most common trigger for alpha-gal allergic reactions, some people are so sensitive that they need to avoid dairy products and other animal products like gelatin. Some medications can be a problem as well. Alcohol and exercise appear to exacerbate the reaction.
“On the bright side, you can eat all the chicken, turkey, and fish you want.”
— via Lifehacker