Alpha-Gal Syndrome

What Is Alpha-Gal Syndrome (AGS)?

Alpha-Gal Syndrome (AGS) is an allergy that some people get after being bitten by certain ticks, especially the lone star tick. These ticks are common in Missouri. When a tick bites you, it can put a tiny molecule called alpha-gal into your body. Some people’s immune systems react to this molecule and make antibodies. This can cause allergic reactions when they eat red meat or other foods from mammals like cows or pigs.

What are the symptoms?

People with AGS can have different symptoms. Some might get hives, stomach problems, swelling or even a serious allergic reaction called anaphylaxis. Diagnosing AGS can be hard. Doctors usually look at your medical history, do a physical exam, and order a blood test to check for alpha-gal antibodies.

How common is AGS?

Recent studies show that AGS is becoming more common, especially in Missouri and nearby states. It’s possible that more than 450,000 people in the U.S. have AGS. In Missouri, between 7,300 and 34,400 people may have been affected since 2021.

What should you do to protect yourself?

  • Try to avoid tick bites by using repellent and checking for ticks after being outside.
  • Learn about AGS and talk to your doctor if you think you have symptoms.

DHSS continues to collect and study information about ticks and tickborne diseases and is working to educate health care providers and the public about prevention and diagnosis. View some of our resources below.

If you have AGS…

Avoid foods and products with Alpha-Gal.

  • Don’t eat red meat from mammals like beef, pork, lamb, venison or rabbit.
  • Be careful with milk and dairy products—some people with AGS react to these, too.
  • Watch out for gelatin and foods cooked with animal fat. These can also contain alpha-gal.
  • Read food labels carefully and ask your doctor or allergist for help if you’re not sure what’s safe for you.
  • Not everyone reacts to every product. Work with your healthcare provider to figure out what you need to avoid.

Prevent future tick bites

  • Use insect repellent with ingredients like DEET, picaridin, IR3535, oil of lemon eucalyptus, or permethrin.
  • Wear long sleeves and pants when you’re outside, especially in grassy or wooded areas.
  • Check your skin and clothes for ticks after being outdoors.
  • Remove ticks quickly and safely if you find one on you.
  • New tick bites can make your allergy worse or bring it back. Protect yourself every time you go outside.

Talk to your health care provider

  • Ask your doctor before taking new medicines or getting vaccines. Some medicines and vaccines might have ingredients from mammals.
  • Get help right away if you have a serious allergic reaction (like trouble breathing, swelling, or hives).
  • Some people may be able to eat red meat again if they avoid new tick bites for a long time. This is different for everyone, so talk to your doctor about what’s best for you.

If you have AGS, remember to avoid foods and products with alpha-gal, protect yourself from tick bites, and talk to your health care provider about your health and safety. If you have questions or need help, reach out to your doctor or local health department.