Version July 2025
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What is alpha-gal syndrome? —
This is a specific type of allergy to red meat. It happens to some people after being bitten by a tick.
Certain types of ticks can pass a molecule called "alpha-gal" to humans when they bite. This molecule is also found in the meat that comes from some mammals. This includes beef, pork, and lamb. For some people, their body reacts in an abnormal way after being bitten by a tick. Their immune system makes proteins called "antibodies" against the alpha-gal molecules. Then, later, if the person eats red meat, they can have an allergic reaction to the alpha-gal in the meat. This can also happen if the person eats something else that comes from a mammal, like milk or gelatin.
In the US, "lone star" ticks are the most common cause of alpha-gal syndrome. A person usually needs to be bit more than once to develop the allergy.
What are the symptoms of alpha-gal syndrome? —
The symptoms are similar to those of other food allergies. But unlike with other food allergies, symptoms usually take longer to happen. A person might not have symptoms until 2 to 8 hours after they ate red meat or a related food. Sometimes, people eat meat for dinner and then wake up in the night because they are having a reaction.
Mild symptoms can include:
●Hives, which are raised patches of skin that are very itchy (picture 1)
●Puffiness of the face, eyelids, ears, mouth, hands, or feet
Severe symptoms are also called "anaphylaxis." They can include:
●Swelling of the throat
●Nausea, vomiting, or diarrhea
●Wheezing, coughing a lot, or trouble breathing
●Feeling dizzy or passing out
●Death
Symptoms can differ from person to person.
Is there a test for alpha-gal syndrome? —
Yes. If your doctor thinks you might have alpha-gal syndrome, they will order a blood test. The test looks for the "IgE" antibody the immune system makes when it has an allergic reaction.
Your doctor or nurse will also do an exam and talk with you. They might do other tests if they think something else might be causing your symptoms.
How is alpha-gal syndrome treated? —
Treatments include:
●Epinephrine – This medicine helps stop the symptoms of an allergic reaction. People who had anaphylaxis before usually get a prescription for epinephrine. It comes in 2 forms:
•A device called an "autoinjector" (sample brand names: Auvi-Q, EpiPen), which has a shot you can give yourself (figure 1)
•A spray that goes in the nose (brand name: neffy) (figure 2)
If your doctor prescribed epinephrine, carry it with you at all times.
Use epinephrine right away if you think you are having a severe allergic reaction. Then, call for an ambulance (in the US and Canada, call 9-1-1). That's because the medicine does not last very long in the body. Symptoms can sometimes come back as the medicine wears off. In the hospital, doctors can watch you and give you more medicine if needed.
●Antihistamines medicines – Your doctor might also recommend an antihistamine, such as cetirizine (sample brand name: Zyrtec). You can get these without a prescription. They can help relieve mild allergy symptoms like itching and hives. They do not treat severe symptoms (anaphylaxis).
Most of the time, alpha-gal syndrome goes away over a period of years if you don't get more tick bites.
How can I prevent an allergic reaction? —
The only way is to completely avoid eating the things you are allergic to. With alpha-gal syndrome, this could include:
●Meat that comes from mammals, like beef, pork, and lamb
●"Organ meats," like kidney and liver
●Milk and dairy products
●Certain medicines and vaccines that contain gelatin
Not everyone reacts to all these things.
How can I prevent getting alpha-gal syndrome? —
The best way is to avoid tick bites.
To protect yourself:
●Wear shoes, long-sleeved shirts, and long pants when you go outside. Keep ticks away from your skin by tucking your pants into your socks.
●Wear light colors, so you can see any ticks on your clothes.
●Use bug spray to keep ticks away. On your skin, use bug spray that has a chemical called "DEET." On your clothes and gear, use bug repellant that has a chemical called "permethrin."
●Check your body for ticks after being outdoors or with dogs. Check your scalp, waist, armpits, groin, and backs of your knees. If you have children, check them for ticks, too.
Patient education: Food allergy (The Basics)
Patient education: Anaphylaxis (The Basics)
Patient education: How to give epinephrine (The Basics)
Patient education: Food allergen avoidance (Beyond the Basics)
Patient education: Food allergy symptoms and diagnosis (Beyond the Basics)
Patient education: Anaphylaxis symptoms and diagnosis (Beyond the Basics)
Patient education: Anaphylaxis treatment and prevention of recurrences (Beyond the Basics)
Patient education: Using an epinephrine autoinjector (Beyond the Basics)
