Red meat allergy caused by a tick bite- a moment of science


It might be your worst nightmare: a serious, potentially fatal, allergy to red meat. The root cause of it might be an even worse thought. A tick bite.

Carolyn Word, an allergist at Charleston Allergy and Asthma, has seen patients with this syndrome, not disease, called Alpha Gal. She says,

“Alpha Gal is now the common term given, and it really is an allergy to galactose-alpha-1,3-galactose. And so it’s a big long word for a little piece of sugar.”

Shortened to alpha gal, it’s found in mammalian meat products: beef, pork, lamb, as well as products derived from those meats such as jello, marshmallow, and sometimes dairy. All are off limits for someone with this allergy which begins with a bite from a tick common in the southeast.

To explain how this happens- let’s start with the basics.

“So an allergic reaction is when the body’s allergy antibodies, called IGE, recognizes a foreign protein. When it recognizes it it’s like a puzzle piece fitting together.”

Carolyn Word, Allergist/Immunologist at Charleston Allergy & Asthma

Setting off a chain of events that results in symptoms ranging from sneezing and swelling to vomiting and diarrhea. She continues,

“Patients without the allergy, their bodies would move on and think nothing of it, but if you make that IGE antibody, the puzzle piece that fits the protein, your body will set off that chain of events.”

In the case of Alpha Gal, its not a protein but a carbohydrate- but it follows the same process.

So how does one who didn’t have an antibody responsible for a red meat allergy suddenly become unable to stomach red meat?

A bug bite. Typically from the Lone Star tick, a type of tick common throughout the southeast. But, Word explains “It doesn’t give you something when it attaches. Its not like the Lone Star tick attaches and transfers the allergy but it does set off a reaction that ultimately results in the production of IGE to alpha gal.”

Now before you decide to never venture outside again so you can continue to enjoy your hamburgers and steak- a couple things to note.

“A tick bite in and of itself does not mean that you have a mammalian meat allergy in your future.”

Numerous tick bites each year result in just a handful of cases, Dr. Word estimates she sees between 50-70 patients annually. If you believe you have a reaction caused by ingesting red meat, she recommends making an appointment at the clinic. 

For more information on how to avoid tick bites while outdoors- check out our Hunt, Hook, and Cook segment on Alpha Gal:

Storm Team 2 Meteorologist David Dickson

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