If you get bitten by a tick, you probably worry about Lyme disease, an infection that spreads from tick bites.
But you could have another health problem after a tick bite. Alpha-gal syndrome (AGS) is an allergic reaction to a substance called alpha-gal. Alpha-gal is a sugar found in some dairy foods and meat that comes from mammals like beef, pork and lamb, but it is not in poultry, fish or shellfish.
Experts think you can get AGS if you’re bitten by the Lone Star tick (Amblyomma americanum). These ticks are found in the southeastern United States and along the Atlantic coast up to Maine. If you’re bitten by a tick in another area, you’re not at risk for AGS.
“There’s something in Lone Star tick saliva that can make your immune system sensitive to alpha-gal,” said Heather Cassell, MD, a pediatric allergist and immunologist with Banner – University Medicine. After a tick bite, you could be allergic to foods containing alpha-gal.
Symptoms of Alpha-gal syndrome
If you have AGS, you might notice signs like:
- Hives
- Itching
- Swelling
- Pain in your abdomen (stomach area)
- Upset stomach
- Diarrhea
In severe cases, you could have anaphylaxis, which is a potentially life-threatening allergic reaction where your blood pressure can drop and your airways can swell, making it hard for you to breathe.
With most food allergies, you may have symptoms right away. But AGS is different. “The symptoms can happen several hours after you eat meat or dairy foods,” Dr. Cassell said. “So it can be hard to figure out exactly what’s causing them without getting medical care.”
Diagnosing AGS
If you think you could have AGS, you may want to see a health care provider who specializes in allergies or immunology. The provider can evaluate you, find a diagnosis and help you learn what you can eat so you don’t have symptoms.
Several steps lead to a diagnosis of alpha-gal syndrome. They can be different based on your situation and what your provider prefers. Your health care provider may:
- Review your symptoms: Tell them exactly what you’ve experienced and whether you think a tick has bitten you. Describe any signs of allergic reactions. Let them know if you’ve had any of these symptoms several hours after eating beef, pork or lamb or eating or drinking dairy products.
- Test for allergies: Skin-prick tests can check for allergic reactions to alpha-gal and other substances. In a skin-prick test, a health care provider puts a small amount of substances that cause allergic reactions on your skin. Then they prick or scratch your skin. If you get a raised red bump (called a wheal), you’re probably allergic to that substance.
- Perform blood tests: Blood tests can measure antibodies in your blood. Your provider will check for high levels of alpha-gal-specific immunoglobulin E (IgE) antibodies. If those levels are high, it could mean your immune system is responding to alpha-gal and you may have AGS.
- Conduct a food challenge: With an oral (by mouth) food challenge, a health care provider has you eat small amounts of something that contains alpha-gal. Then they will watch you closely to see if you have any allergic reactions.
By doing this test in a health care setting, you can get care right away for any symptoms that come up. You should not try to diagnose yourself by eating meat or dairy if you think you might have AGS.
Managing AGS
There’s no cure for alpha-gal syndrome. But you can take these steps to keep it under control:
- Don’t eat beef, pork, lamb, venison, rabbit or other meat from mammals. Eating chicken, turkey, eggs, seafood, vegetables and fruit is OK as long as you don’t have other allergies.
- Talk to your provider about whether you can eat other products that contain alpha-gal, such as gelatin, cow’s milk, foods made from cow’s milk, lard, tallow, suet, meat broth or stock, gravy or bouillon.
- Read food labels carefully.
- Carry an epinephrine auto-injector (EpiPen) for emergencies, in case you’re exposed to alpha-gal.
- Work with your provider to create an emergency action plan.
How to prevent AGS
“The best way to reduce your odds of getting AGS is to prevent tick bites,” Dr. Cassell said. Here are some steps you can take:
- Use tick repellant and wear protective clothes when you’re in woods or grassy areas. Choose long sleeves and long pants and tuck your pants into your socks. Wearing light-colored clothing can make it easier to spot any ticks that get on you.
- When you come indoors after you’ve been in the woods or grassy areas, shower and use a washcloth. Ticks can stay on your skin for hours before biting you, so showering can wash them away.
- Wash your clothes in hot water. If they don’t need to be washed, put them in the dryer for 10 minutes or more on high heat.
- If you find a tick attached to your skin, remove it carefully with tweezers. Don’t try to use heat or petroleum jelly to make it release its bite.
The bottom line
Alpha-gal syndrome (AGS) is an allergic reaction you can get after you’re bitten by the Lone Star tick. It can make you allergic to beef, pork, lamb and some dairy products.
A health care provider can test you to see if you have AGS. If you do, you can prevent symptoms by avoiding eating foods that have alpha-gal in them. You may also need to carry an EpiPen in case you eat or drink something with alpha-gal by mistake.
If you think you might have AGS, talk to a health care provider. They can evaluate your symptoms, offer a diagnosis and help you understand what you can and can’t eat. If you would like to connect with an allergist or immunologist who can help, reach out to Banner Health.
