Alpha-gal syndrome

Date Updated: 08/08/2025

Overview

Alpha-gal syndrome is a type of food allergy. It can happen after a tick bite. The allergy is to red meat and other products that come from mammals. Alpha-gal syndrome can be life-threatening.

In the United States, the condition most often begins with the bite of the lone star tick. Other types of ticks cause the condition in different parts of the world, mainly in parts of Europe, Australia, Asia, South Africa, and South and Central America.

Alpha-gal syndrome causes mild to intense allergies to red meat, such as beef, pork or lamb. It also can cause reactions to other foods that come from mammals, such as dairy products or gelatin.

Some people may have alpha-gal syndrome and not know it. There are people who have serious allergic reactions, called anaphylactic reactions, for no known reason. Because the reactions can be delayed for hours, researchers think that some of these people may be affected by alpha-gal syndrome.

The only treatment for alpha-gal syndrome is to not eat red meat or other products from mammals that can trigger reactions. A serious allergic reaction may need medicine called epinephrine and treatment in an emergency room.

Symptoms

An alpha-gal allergic reaction often starts about 2 to 6 hours after you eat something with the alpha-gal molecule.

Symptoms may be mild or lead to serious illness, and include:

Hives and itching.
Swelling of the lips, face, throat or eyelids.
Wheezing or shortness of breath.
Stomach pain, diarrhea, nausea or vomiting.

Symptoms of alpha-gal syndrome may lessen or go away over time.

When to see a doctor

Get help if you have food allergy symptoms after you eat, even several hours after you eat. See your main healthcare professional or an allergy specialist, called an allergist.

Get emergency medical treatment if you have symptoms of a serious allergic reaction that causes trouble breathing, called anaphylaxis. Symptoms may include:

Trouble breathing.
Fast, weak pulse.
Dizzy or lightheaded feeling.

Causes

Most people with alpha-gal syndrome in the U.S. get the condition from lone star tick bites. Other types of ticks can cause the condition too, mainly in parts of Europe, Australia, Asia, South Africa, and South and Central America.

Experts think the ticks that cause alpha-gal syndrome carry alpha-gal molecules. When a tick that carries these molecules bites a human, the tick sends alpha-gal into the person's body. Experts don't know why some people have strong reactions to alpha-gal.

Risk factors

You're at higher risk if you live or spend time in areas that have ticks that carry alpha-gal. Having more than one tick bite seems to raise the risk even more.

Complications

Alpha-gal syndrome can cause a serious allergic reaction called anaphylaxis. It can be deadly without treatment. A prescription medicine called epinephrine treats anaphylaxis. You can give yourself a shot of epinephrine, also called adrenaline, with a device called an autoinjector (EpiPen, Auvi-Q, others). You also need to go to an emergency room.

Anaphylaxis symptoms can include:

Tight, narrow airways.
Swelling of the throat that makes it hard to breathe.
Fast pulse.
Feeling dizzy or lightheaded, or passing out.

Healthcare professionals think that some people who get anaphylaxis often and for no clear reason may be living with alpha-gal syndrome that hasn't been diagnosed.

Reactions to medicines and vaccines

Although it's rare, people with antibodies related to alpha-gal syndrome can have allergic reactions to certain medicines and vaccines. These may include the cancer medicine cetuximab (Erbitux). Talk to your healthcare professional before taking a new medicine or getting a vaccine.

Prevention

The best way to prevent alpha-gal syndrome is to prevent tick bites. Stay away from areas where ticks live. Be careful in wooded, bushy areas with long grass. You can lower your risk of getting alpha-gal syndrome by following some simple tips:

Cover up. When you're in wooded or grassy areas, wear shoes, long pants tucked into your socks, a long-sleeved shirt, a hat and gloves. Try to stay on trails. Don't walk through low bushes and long grass. Keep dogs on leashes.
Use bug spray. Apply insect repellent with 20% or more of the ingredient DEET to your skin. Adults should apply it to children. Stay away from hands, eyes and mouths. Follow directions carefully. Put products with the ingredient permethrin on clothing or buy pretreated clothing.
Check yourself, your children and your pets for ticks. Take a good look after you spend time in wooded or grassy areas.
Shower as soon as you come indoors. Ticks often stay on your skin for hours before they attach themselves. Shower and use a washcloth to try to remove any ticks.
Remove a tick with tweezers as soon as you can. Gently grasp the tick near its head or mouth. Don't squeeze or crush the tick. Pull out the whole tick with a careful, steady grip. Then get rid of the tick. Clean the area of the bite.

Diagnosis

To diagnose alpha-gal syndrome, a healthcare professional asks about your symptoms and your medical history and does an exam. A blood test can confirm that there are alpha-gal antibodies in your blood and measure the amount. But it's possible to have alpha-gal antibodies without having alpha-gal syndrome.

Treatment

Alpha-gal syndrome treatment involves not eating the foods that cause your reaction. Always check the ingredient labels on store-bought foods. Make sure they don't have red meat or meat-based ingredients.

Ask your healthcare professional for a list of foods to not eat. These include meat extracts used in flavoring. The names of some meat-based ingredients make them easy to miss.

Be aware that some medical products made from animals may have alpha-gal. These might include heart valves from pigs and cows, lab-made proteins called monoclonal antibodies that fight diseases, the blood-thinning medicine heparin and some medicines to treat snake bites. But reactions to these products from people with alpha-gal syndrome are rare.

For a mild allergic reaction, an allergy medicine might help. For a more intense reaction, you may need a shot of epinephrine and emergency care. Many people with allergies carry a device called an epinephrine autoinjector. It's a syringe and needle that gives you a single dose of medicine when you press it against your thigh.

If you've been diagnosed with alpha-gal allergy, your healthcare professional is likely to prescribe an epinephrine autoinjector and teach you how to use it.

Lifestyle and home remedies

To keep from having an alpha-gal reaction, don't eat foods that have the following:

Beef.
Pork.
Lamb.
Organ meats, such as kidneys, livers, intestines and sweetbreads.
Gelatins and gelatin-coated medicines.

Check soup stock cubes, gravy packages and flavor ingredients in packaged products.

Be extra careful when you dine out. Even a small amount of meat can cause a serious reaction.

Do what you can to lower your risk. If you're worried that you may be allergic to something in a food, don't try it. Also think about bringing your own food to a party if guests are sharing a cooking surface to make food.

Preparing for an appointment

You may start by seeing your main healthcare professional. You may be sent to a specialist in allergies, called an allergist. Here are some tips to help you make the most of your appointment.

What you can do

Take a family member or friend along if you can. Someone who's with you can help you gather information.

Make a list of:

Your symptoms. What happens after you eat red meat? How long did the reaction take? What type of red meat did you eat and how much?
Your tick bites. List how many you've had and when you got them. Include how much time you spend outdoors in areas ticks are likely to be.
All medicines, vitamins or supplements you take, including dosages.
Questions you have.

Some questions to ask include:

Are my symptoms likely caused by a red meat allergy?
What else might be causing my symptoms?
What tests do I need?
What's the best treatment?
Should I see a specialist?
Are there brochures or other printed material that I can have? What websites do you suggest?
Do I need to carry an epinephrine autoinjector?

What to expect from your doctor

Your healthcare professional may ask you questions such as:

Did you take allergy medicines that you can get without a prescription, such as antihistamines? If so, do they help?
Do you get symptoms when you eat any foods other than meat or meat products?
How bad are your symptoms?
What, if anything, seems to make your symptoms better?
What, if anything, seems to make your symptoms worse?

What you can do in the meantime

If you think you have alpha-gal syndrome, don't eat red meat until your appointment. If you have a serious reaction, get emergency help.