Alpha-gal Syndrome

Alpha-gal syndrome (AGS) is an allergy to red meat, meat products and dairy that you develop after getting bitten by a tick. Products you might have an allergic reaction to include:

• Meat from mammals (like beef, pork and lamb)
• Foods or products made with animal fat
• Certain medications
• Cow’s milk and products made with milk

Alpha-gal is a carbohydrate (sugar) molecule found in most mammals (other than humans) and tick saliva. Not everyone who gets a tick bite develops alpha-gal syndrome. And it’s unlikely that you’ll have a reaction to every food or product that could contain alpha-gal.

Symptoms of alpha-gal syndrome

Symptoms of alpha-gal syndrome range from mild to severe. Sometimes, they can be life-threatening. Symptoms include:

• Skin changes, like itching, hives or flushing
• Swelling of your lips, eyelids, throat, tongue or face (angioedema)
• Respiratory symptoms, like cough, shortness of breath or wheezing
• Digestive symptoms, like belly pain, diarrhea, heartburn, nausea or vomiting
• Dizziness or fainting
• Joint pain

You might have digestive or skin symptoms on their own, or you might experience other symptoms along with them.

Alpha-gal can cause severe allergic reactions, including anaphylaxis. Anaphylaxis can make it difficult to breathe and cause a severe drop in blood pressure. It can be fatal. Call 911 (or your local emergency service number) or go to the ER at the first sign of severe symptoms.

How long after eating meat would I have symptoms?

Unlike many food allergies, which happen right after eating, symptoms of alpha-gal can happen two to six hours after eating meat or dairy. Medications that contain alpha-gal might be more likely to cause an immediate reaction.

Alpha-gal syndrome causes

You get alpha-gal syndrome from a tick bite. Lone star ticks are the most common cause. But bites from black-legged (deer) ticks and other species can also cause it.

Ticks have alpha-gal molecules in their saliva. Alpha-gal is a carbohydrate that’s found in most mammals, but not in people. When a tick bites you, you can become sensitized to the molecule and develop an allergy. Healthcare providers aren’t sure why some people develop an allergy after a tick bite and others don’t. Additional tick bites may make your symptoms worse or more frequent.

Where is it most common?

AGS is most common in South, East and Central parts of the U.S. This is where lone star ticks are most often found.

How doctors diagnose alpha-gal syndrome

Healthcare providers diagnose alpha-gal syndrome with allergy blood tests and skin tests. It can be tricky to diagnose the cause of your reaction for many reasons:

• Tick bites are painless and often don’t leave a mark. Many people who develop tick-borne illnesses don’t realize they’ve been bitten.
• Unlike other food allergies, delayed reactions to alpha-gal can make it hard to know what’s causing your symptoms.
• Not everyone with alpha-gal has the same symptoms or reactions to the same foods and products.

It might be helpful to note when you have reactions and anything you’ve eaten or come in contact with that day. This might help you and your provider figure out the cause.

How is alpha-gal treated?

You can manage alpha-gal by avoiding foods, medications and personal care items that contain certain animal products. Your healthcare provider can work with you to come up with a list of potential triggers to avoid. New treatments, like omalizumab (Xolair®) injections and oral immunotherapy (OIT), might reduce your risk of a severe reaction if you’re accidentally exposed to alpha-gal.

Your provider will also prescribe antihistamines or an epinephrine auto-injector (EpiPen® or Auvi-Q®) to use if you have an unexpected reaction. A nasal spray of epinephrine (neffy®) is another option.

If you have to take a medication that could cause a reaction, your provider will work with you to determine your treatment options.

You should also avoid getting additional tick bites. They can make you more likely to have severe reactions.

What foods should I avoid if I have alpha-gal syndrome?

Not everyone with alpha-gal syndrome reacts to the same foods and products. Some things you might need to avoid include:

• Meat from mammals, including pork, beef, rabbit, lamb, goat and venison
• Foods made with or cooked in animal fat
• Cetuximab, a medication that treats certain types of cancer

While not as common, you might also react to:

• Milk and products that contain milk
• Household products like lanolin, tallow and suet
• Food or medications made with gelatin or glycerin, magnesium stearate or bovine extract
• Foods made with carrageenan, an additive often used to thicken and preserve nut milks, meat products and yogurt
• Certain vaccines that could be made with animal products

Ask your allergist about which foods and products are safe for you.

When should I see my healthcare provider?

Talk to your healthcare provider if you have symptoms of alpha-gal syndrome. If you have an AGS diagnosis, check with your provider before getting vaccines to see if they could potentially cause a reaction.

Does alpha-gal syndrome ever go away?

Sometimes. Some people find they can reintroduce foods containing alpha-gal without symptoms after avoiding them for a year or two. Avoiding additional tick bites can make it more likely that AGS gets better. But you should talk to your healthcare provider before trying to eat foods that could cause a reaction.

Can it be prevented?

The most effective way to avoid getting AGS is to avoid getting tick bites. Ways to reduce your risk include:

• Don’t go off the trails in wooded and grassy areas.
• Cover up as much skin as possible. Wear long-sleeved clothing. Tuck socks into your shoes or pants. Apply permethrin to clothing or buy pretreated clothing. Don’t apply permethrin to your skin.
• Use U.S. Environmental Protection Agency (EPA)-approved insect repellents.
• Check yourself and your pets for ticks after being outdoors. It’s also helpful to take a shower after you’ve been outside.
• Remove ticks right away. Clean the area with rubbing alcohol and a cotton ball. Use tweezers to grasp the tick near its head or mouth. Pull it out carefully without crushing it. Clean the area with soap and water.