Alpha-gal Syndrome: What You Need to Know About the Red Meat Allergy

The most common food allergies in the U.S. are those caused by things like eggs, milk, and nuts. Red meat allergies used to be nearly nonexistent. But over the last 15 years, alpha-gal syndrome is becoming more common. The CDC estimates that this condition could affect as many as 450,000 people in the U.S.

Alpha-gal syndrome is an allergy to a sugar called galactose-alpha-1,3-galactose (often called “alpha-gal”). The sugar is found in the meat of mammals. More specifically, it’s found in beef, lamb, and pork, as well as other types of meat, like rabbit or goat. 

There’s no cure or treatment for alpha-gal syndrome. So the best way to protect yourself is to recognize the symptoms so you can take steps to avoid a life-threatening reaction.

What are the symptoms of alpha-gal syndrome? 

Alpha-gal syndrome symptoms are similar to those of a typical allergic reaction. Mild symptoms can include hives and itchy skin. More severe reactions, like anaphylaxis, can be deadly. Symptoms include:

• Throat tightness

• Swelling of the lips or tongue

• Trouble breathing

• Abdominal pain, vomiting, and diarrhea

• Dizziness or loss of consciousness

Unlike a typical food allergy that tends to happen quickly, alpha-gal syndrome reactions tend to be much more delayed and occur 2 to 6 hours after eating the food. This means that you might be able to eat a full meal with red meat and not feel any discomfort until hours later.

What type of meat can trigger alpha-gal syndrome?  

The most common foods with alpha-gal are certain types of meat. These include:

• Beef

• Pork

• Lamb

• Bison

• Rabbit

• Venison

• Goat  

Some people with alpha-gal syndrome may have reactions to foods other than meat that contain small traces of alpha-gal. This includes dairy products like milk and cheese. It can also include products made with gelatin, like marshmallows or Jell-O. 

Experts also know of one medication — the cancer drug cetuximab — that triggers alpha-gal syndrome. Interestingly, this is how it was discovered.

When cetuximab was released in 2006, healthcare providers noticed that cancer patients began having allergic reactions to the drug. After some lab tests, it was found that the people had reacted to alpha-gal, an ingredient in cetuximab. 

Providers tried to see if this type of alpha-gal sensitivity existed in their regular patient populations. They found it in almost all people who had complained of red-meat allergies.

What causes alpha-gal syndrome?

In the U.S., the main cause of alpha-gal syndrome seems to be bites from the lone star tick. Experts discovered this when they noticed that most cases were in the Southeastern U.S., where the lone star tick is more common. But in more recent reports, a growing number of cases have been identified in mid-Atlantic and Midwestern states.

But the CDC has also identified cases in states where there are no known populations of the lone star tick. So experts are still learning about what causes alpha-gal syndrome and its association with tick bites.  

Not everyone bitten by a lone star tick will develop an alpha-gal allergy. It’s still not known how tick bites lead to alpha-gal syndrome.  

What is the treatment for alpha-gal syndrome?

Alpha-gal syndrome may gradually go away on its own. Some people grow out of the allergy over time. Eventually they can bring red meat back into their diet. 

But until then, the best treatment for alpha-gal syndrome is to avoid foods with alpha-gal that can trigger a reaction. Foods to avoid include:

• Red meat that comes from mammals (beef, pork, and lamb) 

• Other types of meat (like bison, rabbit, venison, and goat)  

• Dairy products 

• Foods that contain gelatin  

Someone with alpha-gal syndrome does not necessarily have to become a vegetarian. There are plenty of types of meat without alpha-gal, such as poultry and seafood. But keep in mind these can sometimes be processed with alpha gal-containing foods, such as chicken or turkey sausage in a beef or pork casing.

Another important way to treat alpha-gal syndrome is to avoid more tick bites. This is because repeat tick bites can increase how someone reacts to alpha-gal on lab tests. The allergy may then last longer.

Someone with alpha-gal syndrome may accidentally eat a food containing alpha-gal and have a reaction. If that happens, it should be treated like any other allergic reaction to food: 

• A mild reaction, like itching, can be treated with an antihistamine like diphenhydramine (Benadryl). 

• Any symptoms beyond that should be treated like potential anaphylaxis. This means you should call 911 or go to the nearest emergency room. And use injectable epinephrine, like an EpiPen or Adrenaclick, if it’s prescribed to you. 

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Written by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

Reviewed by:

Karla Robinson, MD

Karla Robinson, MD, is a medical editor for GoodRx. She is a licensed, board-certified family physician with almost 20 years of experience in health through varied clinical, administrative, and educational roles.

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