How a Tick Bite Can Make You Allergic to Meat

Bad news, burger fans: A tick bite has the potential to permanently remove red meat from your menu. A meat allergy known as alpha-gal syndrome (AGS) appears to be triggered by a tick bite, researchers say.

Case counts are growing, too. There were only 24 reported cases in the United State in 2009. By 2018, the number topped 34,000.

In fact, a federal report noted that AGS has become the leading cause of anaphylaxis in a southeastern registry of patients.

So, what do we know about this emerging allergy that threatens to cool the coals on a favorite backyard grill option? And what can you do to avoid it? Allergist Arnaldo Perez, MD, offers some food for thought.

What is alpha-gal syndrome?

AGS is a severe allergy to a sugar molecule called galactose-alpha-1, 3-galactose (commonly referred to as alpha-gal), which is found in the cells of most mammals. Symptoms appear after eating meat or other food products with animal connections, such as dairy or gelatin.

The syndrome and its connection to ticks were discovered by researchers in 2009. AGS has been increasingly studied in the years since to gain a better understanding of it.

“Tick bites are an unusual way to become allergic to a substance,” says Dr. Perez. “This is a recent association, for sure. It’s still somewhat rare, but it’s something to be aware of, especially if you’re having unexplained allergic reactions.”

What tick causes the red meat allergy?

One little bugger — the lone star tick — appears to be the main source of AGS in the United States. The tick has long called southeastern states home, but its range has now expanded into the Midwest and Northeast.

The lone star tick is very aggressive, according to the Centers for Disease Control and Prevention (CDC). It’s most active (and biting) from early spring through late fall.

The name comes from the appearance of the adult female, which has a single white dot — or “lone star” — on its back. Aside from AGS, its bite can lead to Lyme disease, Heartland virus, Bourbon virus and Southern tick-associated rash illness (STARI).

However, other tick species haven’t been ruled out as potential sources of AGS. “There are other parts of the world where this phenomenon has been identified, and the lone star tick is not there,” notes Dr. Perez.

Symptoms of AGS

Like most food allergies, reactions can range from mild to life-threatening. Signs of an AGS reaction include:

• Skin rashes or hives, which are present in the vast majority of AGS reactions.
• Gastrointestinal issues such as heartburn, severe stomach pain or diarrhea.
• Difficulty breathing.
• Swelling of the lips, throat or tongue.

What’s unusual about AGS reactions, however, is how long it takes for symptoms to appear. Most AGS reactions occur three to six hours after an exposure. (For comparison, most food allergy reactions take place within minutes.)

“That delay can make it more challenging to make a direct association with what was eaten,” says Dr. Perez.

Testing for AGS

Talk to your healthcare provider if you show signs of AGS. Confirmation of the syndrome typically comes through a blood test that looks for antibodies to alpha galactose. A skin test also may be done.

Foods and products to avoid if you have AGS

The no-no list starts with meat from mammals. This includes beef, pork, lamb and venison, as well as meat from furry, warm-blooded creatures. “All of these can cause a reaction,” stresses Dr. Perez.

The good news? Poultry and fish don’t contain alpha-gal and can stay in your diet.

Someone with AGS also may need to avoid:

• Lard (rendered pig fat).
• Gelatin, which is made from boiling animal bones, skin and tissue.

Countless medications, personal healthcare items and household products may also contain alpha-gal. It’s best to discuss specifics with your allergist or healthcare provider to determine your risk.

Treatment for AGS reactions

Some people with AGS will be prescribed an epinephrine auto-injector — more commonly known by the name EpiPen® — for potential use in case of an anaphylactic reaction, says Dr. Perez.

Over-the-counter antihistamines can be used to help ease symptoms for less severe reactions.

There isn’t a current cure for AGS.

How to prevent AGS

Given that tick bites are the main cause of AGS, taking proper precautions while outdoors is your best defense against the syndrome, says Dr. Perez. He recommends:

• Wear clothing that completely covers your skin in areas with tick activity. That means long-sleeve shirts, pants and high socks. Tucking your pant legs into your socks can provide added protection.
• Use bug sprays on your clothes and skin to ward off creepy crawlies. DEET-based repellants are safe to use.

Make sure to check your clothing and skin for ticks before coming back inside, too. Remove any attached ticks with tweezers ASAP. (Review CDC guidance on tick removal.)