People’s Pharmacy | Tick bite leads to scary allergy to meat

When most people get bitten by a tick, they worry about Lyme disease and other infections such as Rocky Mountain Spotted Fever. Increasingly, however, people are beginning to recognize that some tick bites can lead to a delayed allergic reaction to eating meat.

This unusual reaction was first described in the medical literature 17 years ago by a group of researchers at the University of Virginia (Journal of Allergy and Clinical Immunology, Feb. 2009). It took many years for emergency physicians and other health professionals to appreciate the significance of this allergy.

That is partly because the trigger is complicated and unlike other allergies. First, there is the tick bite. Originally, lone star ticks (Amblyomma americanum) were the only suspects. Now, scientists have linked this problem to two other species as well, black-legged ticks (Ixodes scapularis) and western black-legged ticks (Ixodes pacificus).

Days to weeks later, the person enjoys a BLT or a burger for supper, goes to bed at the usual time and awakens in distress hours later. Symptoms range from horrible hives to vomiting and diarrhea or tongue swelling and wheezing.

The cause is a reaction to a sugar in mammalian meat, galactose-alpha-1,3-galactose. The treatment is to avoid eating mammals–no beef, pork, lamb or other mammalian meat. Birds and fish do not carry this sugar, so people with alpha gal allergy can safely eat them.

Readers describe in vivid detail what this experience is like. One person reports: “Six years ago, I headed to the ER with hives and intolerable itching. While waiting in triage I went into anaphylaxis. I was given IV Benadryl and epinephrine.

“The doctors had no idea what caused these symptoms. A nurse who happened by said it was perhaps a tick bite meat allergy.

“My primary doctor referred me to an allergist, who had never heard of alpha gal. He looked it up and got very excited to see his first possible case! He did not have the alpha gal blood test available.

“On my own, I researched alpha gal and began meat avoidance. My primary doctor prescribed an Epipen just in case. I have had reactions to flavorings, gelatin and other hidden ingredients.

“I worry about being hospitalized and unable to speak up for myself. After surgery two years ago with a 10-day hospital stay, the staff repeatedly delivered food I couldn’t eat despite alpha gal being on my records.”

That is a legitimate concern. Here is what another reader told us: “I recently needed an emergency appendectomy. No one at the hospital had ever heard of alpha gal–not the attending doctor, not the nurses, nor the surgeon. Fortunately, they listened to me and took it seriously.

“As I was rushed from the scan to pre-op, I was told to be certain that the anesthesiologist understood what this condition involved, because some of the drugs they use may have substances derived from beef! The anesthesiologist made them hold the surgery until he consulted his colleagues so that he could avoid bovine ingredients.”

We heard from many more readers on this topic. This is one of our favorites: “You may have saved my mother’s life many years ago by reporting on alpha gal allergy. Her mysterious symptoms had gradually increased over time to difficulty breathing when I learned of the tick-related allergy.”

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In their column, Joe and Teresa Graedon answer letters from readers. Write to them in care of this newspaper or e-mail them via their Web site: www.peoplespharmacy.com. Their newest book is Top Screwups Doctors Make and How to Avoid Them (Crown).