Most people are aware that tick bites can transmit infections such as Rocky Mountain Spotted Fever and Lyme disease. There is another condition caused by tick bites, however. It’s called alpha-gal allergy.
What Is Alpha-Gal Allergy?
Scientists have known for several years that the bite of a lone star tick (Amblyomma americanum) can trigger a violent reaction to red meat. In this condition, people react to a sugar found in the blood of all mammals other than primates. (Humans are primates.) The sugar is galactose-alpha-1, 3-galactose, hence the term alpha-gal allergy. Affected individuals can develop severe symptoms hours after consuming a hamburger or pork chop. Fish and poultry don’t cause the reaction.
Researchers at the University of North Carolina recently made a report to the American Academy of Allergy, Asthma and Immunology annual conference in San Francisco on Feb. 23, 2019. They have found that saliva from both lone star and deer ticks can trigger alpha-gal allergy. The ticks do not have to have fed on another animal first. This greatly increases the likelihood that someone bitten by one of these ticks will develop the allergy to red meat.
What Does Alpha-Gal Allergy Feel Like?
Imagine waking up in the middle of the night with itchy hives all over your body. You might also find you were having trouble breathing. A trip to the ER could safe your life, but the cause of your mysterious ailment might not be diagnosed.
People who have had such a scary episode are usually questioned about their exposure to an allergen just before the reaction started. In most cases, they were sound asleep. No obvious triggers are apparent.
A medical detective, Thomas Platts-Mills, MD, uncovered the cause of these delayed allergic reactions (Journal of Allergy and Clinical Immunology, online March 19, 2014). Tick bites from lone star or even deer ticks can trigger a chain reaction that results in allergic reactions three to seven hours after eating meat (beef, pork, lamb or other mammals). The time delay and the two-step process (first tick bite, then allergy to alpha-gal sugars in meat) explain why this problem may not be diagnosed promptly.
Alpha-Gal Could Be Deadly:
One visitor to our website recounted this terrifying experience:
“I have alpha-gal allergy after being bitten by about 30 seed or nymph ticks three years ago. About 10 days later, six hours after eating a steak, I had complete cardiac arrest as a result of severe anaphylaxis. I almost died.
“A year later I ate pasta sauce that I didn’t know had beef stock in it, and five hours later I had complete respiratory collapse. As a result, I almost died three times in one hour. My blood pressure dropped to 60 over 40.
“I am now allergic to milk, cheese, whey and other dairy products as well as gelatin and any mammalian meat or by-product. I need to check all food and medications carefully before eating or taking them. The casing on many capsules is gelatin and could send me into anaphylaxis.”
Diagnosing Alpha-Gal Allergy:
The history of tick bites and later a delayed allergic reaction to eating meat is a tip-off. There is also a blood test that can help with diagnosis of alpha-gal allergy. Initially, many doctors were unfamiliar with this allergy and didn’t know how to make the diagnosis.
Another reader shared his frustration at having been ignored for years:
“I have had serious allergic reactions for almost 20 years and have almost died three times. Despite this, doctors told me that my allergies (to beef, pork or lamb) were all in my head.
“When I needed open-heart surgery, I mentioned my allergies. The surgeon sent my blood to the University of Virginia, and I was diagnosed with alpha-gal allergy.”
The only known solution to this unusual and potentially deadly reaction is to carefully avoid all meat from mammals. That means no burgers, hot dogs, bacon, steak, lamb chops, ribs or other common cookout fare. Chicken and fish are fine, however.
To learn more about this unusual condition, you may be interested in listening to our hour-long radio interview with Dr. Platts-Mills as well as a young man with alpha-gal allergy and the allergist who diagnosed him. Find it here.
Preventing tick bites whenever possible with protective clothing and careful inspections is the first step in avoiding alpha-gal allergy. The next is to be aware that a delayed reaction to meat could be a signal of a serious problem.