Alpha-gal allergy; tick bites; anaphylaxis
Question:
6/17/2017
I have a patient with sudden onset meat allergy (specifically beef, pork, lamb but not other meats) after being bit by a tick in a deer tick-endemic area. He cannot eat raw or medium rare meat but can eat well cooked meat without problem. Is this typical? Antibodies were moderate and positive for the alpha-gal as well as beef, pork, and lamb IgE. Also, is there any information about prognosis for this allergy long-term?
Answer:
Alpha gal is certainly becoming an increasing issue for some of our A/I colleagues and can be a challenge to diagnose. The symptoms of allergic reaction after eating "meat" that can be delayed for several hours is typical of this syndrome. As is a history of antecedent "tick bites". For more insight we have asked Dr. Scott Commins for his thoughts:
"The difference in meats and resulting symptoms (or lack thereof) is likely due to the amount of fat content present. It is not unusual for some patients to be able to tolerate some amount of lean meat on occasion but not fattier cuts. Whether symptoms occur is also modified by exercise, medications, alcohol, and illness. We have found, however, that any non-primate mammalian meat carries a risk of causing a reaction – thus, avoidance is still recommended.
In terms of prognosis, the alpha-gal allergy does appear to wane over time and may fully resolve for some patients. Unfortunately, additional tick bites can cause the allergy to perpetuate and even return once resolved."
I hope this has been helpful.
Drew Murphy, MD FAAAAI