Meat allergy...from a tick bite?

Imagine you are at a nice restaurant celebrating your birthday.  It’s a special occasion so you decide to order a steak, one of your favorite foods.  Soon after enjoying your meal, you start to feel funny—you start to get an itchy rash, your tongue and throat begin to swell.  You are in anaphylactic shock—caused by an allergic reaction. (Other signs and symptoms of anaphylaxis can be found here).  ‘’But I’m not allergic to anything,” you might say.  You’ve eaten steak many times and never had this kind of reaction.  At the hospital, your doctor may ask, “Were you bitten by a tick recently?”  Confused, you answer “Yes, but I don’t see what that has to do with my allergy.”  Strangely enough, some tick bites may be the cause for a late-onset allergy to red meat (Commings et al, 2011).

We tend to think that allergies are something we are born with, maybe to peanuts or an insect sting or bite.  But it is possible to develop an allergy later in life.  In this case, a tick bite from the lone star tick (pictured below) causes an allergy to the molecule galactose-alpha-1,3-galactose (alpha-gal), an oligosaccharide that is also found in red meat.  Patients who are bitten by this tick see serum levels of the IgE antibody for alpha-gal increase by twenty times, or more (Commings et al, 2011).  The antibodies are proteins in the blood that bind to antigens such as alpha-gal.   This kicks off the body’s immune response that leads to anaphylaxis.  It may take up to eight hours for a reaction to occur after eating the meat (Encyclopedia of Life).

Amblyomma americanum (Lone Star Tick)

The lone star’s tick territory ranges from Texas to as far north as Maine, but is mainly found in the southeastern United States.  Areas of the Midwest, including the St. Louis area are also home to these ticks.  Their habitat consists of meadows and wooded areas (Encyclopedia of Life).  I personally know two people who have been bitten by the lone star tick and subsequently developed an allergy.  As someone who enjoys steaks and hamburgers (maybe a little too much), I will certainly be careful to avoid situations where I can be bitten.

Territory of the Lone Star Tick

Sources:

Amblyomma americanum: Lone Star Tick. (n.d.) In Encyclopedia of Life. Retrieved from         http://www.eol.org/pages/514547/overview

American Academy of Allergy Asthma & Immunology. (n.d.). Anaphylaxis. Retrieved from: http://www.aaaai.org/conditions-and-treatments/allergies/anaphylaxis#Tab2

Commings, SP, James, HR, Kelly, LA, Pochan, SL, Workman, LJ, Perzanowski, MS, . . ., Platts-Mills, TAE. (May 2011). The relevance of tick bites to the production of IgE antibodies to the mammalian oligosaccharide galactose-α-1,3-galactose. The Journal of Allergy and Clinical Immunology, 127(5), 1286-1293. http://dx.doi.org/10.1016/j.jaci.2011.02.019