There is a new trigger for anaphylaxis (severe allergic reaction) or, more likely it was a cause of anaphylaxis called “idiopathic anaphylaxis” because it was not recognized. It’s called: “alpha-gal” food allergy.
How it happens:
A tick bite by the Lone Star Tick or after receiving the medication Cetuximab causes the body to produce allergic (IgE) antibodies to alpha-gal. If meat is eaten within 1-4 weeks, a serious reaction can occur. Over time, the level of IgE antibodies decreases. However, if the person is again bitten by the tick, then re-sensitization occurs and the person is at risk for another severe allergic reaction.
- Onset of generalized hives or anaphylaxis occurring 3-6 hours after eating beef, pork, or lamb.
- Some reactions occur to milk, which contains alpha-gal (especially new-onset milk allergy after age 6 years old)
- Most patients are sensitized to gelatin and some patients will have allergic reaction to gelatin
- Most patients are allergic to cat (Fel d5w), but may have a negative cat Immunocap lab test (Fel d 1)
- Some patients have hives or hand irritation after handling raw meat, especially if there are cuts on the hands
Most cases have been found where tick bites to the Lone Star tick (Amblyomma americanum) occur. This is Southeastern U.S. and southern Australia. But,….people travel to the Southeast, get tick bites and return home!
Reactions don’t happen every time with eating meat (related to quantity of meat eaten)
- Blood test for IgE antibody to galactose-alpha-1,3-galactose
- Allergy skin test to fresh and cooked meat
- Food challenge using bacon or pork sausage or BBQ ribs (higher risk with fattier meats!)
If you have experienced a severe reaction after eating meat, see me at Family Allergy & Asthma Care of Montana. Meat, it’s what’s for supper (unless you are allergic)!
This information is solely for informational purposes and not intended as a substitute for consultation with a medical professional.