What is Alpha-Gal Syndrome?

You’ve probably heard of alpha-gal syndrome, and you may know that those who have it can’t eat red meat. But what exactly is alpha-gal syndrome? How do you get it? Ticks.

Alpha-gal syndrome, or AGS, is spread to humans by the bite of infected ticks. These ticks picked up the alpha-gal molecule by biting a mammal that naturally carries the molecule in their blood. Most mammals do. But humans are one of the few exceptions.

Because we don’t have this molecule in our blood, we can have an allergic reaction when our body recognizes this molecule as an intruder and tries to defend itself. This is how humans develop AGS. However, not every person bitten by these ticks will end up with AGS.

Which ticks can carry alpha-gal?

Lone star ticks most often are associated with transmitting alpha-gal. However, black-legged ticks and western blacklegged ticks can also carry the molecule and pass it along to humans. The U.S. Centers for Disease Control and Prevention have received most reports of AGS from states in the southern, eastern, and central U.S. 

How do you know if you have AGS?

The allergic reaction, which can be mild to severe, usually occurs 2 – 6 hours after eating red meat, dairy products or other products that contain alpha-gal. It may take weeks to months after being bitten by an infected tick for symptoms to appear.

Symptoms can include hives or an itchy rash; nausea or vomiting; heartburn or indigestion; severe stomach pain; diarrhea; dizziness or faintness; a drop in blood pressure; cough, shortness of breath or difficulty breathing; swelling of the lips, throat, tongue or eye lids. Some people can have a severe reaction called anaphylaxis, which is a medical emergency.

While allergic reactions are more likely to occur after eating meat from mammals, AGS can cause an allergic reaction to anything that contains alpha-gal, including gelatin made from beef or pork and products made from meat broth and mammal fat. Nonfood products, such as medications with gel coatings, can also cause reactions.

A person may not react to every product that contains alpha-gal, and a person can react differently each time they are exposed to the same product.

For more information about food and nonfood products that may contain alpha-gal, visit the CDC website. 

How do you avoid AGS?

Take steps to avoid tick bites. You probably know where you are most likely to pick up ticks: woody, brushy, and grassy areas. But you may even have them in your home lawn, especially if you have pets or live in areas where stray pets or wild animals may enter the yard.

If you are in an area where you know you could likely pick up ticks:

• Tuck your pant legs into the tops of boots or socks.
• Tuck in your shirttail.
• Use an effective tick repellant. There are permethrin-based products specifically used to treat clothing. These should never be sprayed on the skin. Effective repellants for use on the skin include those that contain DEET, picaridin, IR3535, Oil of Lemon Eucalyptus (OLE), para-menthane-diol (PMD), or 2-undecanone. Always read and follow the label directions on any insect repellant.
• Shower within two hours of coming indoors to wash off any unattached ticks. This is also a good way to check yourself for ticks.
• Wash and dry clothing using hot water and high heat when you come indoors. Cold and warm temperatures do not kill ticks.
• Consult your veterinarian about treatments to protect your pets from ticks. This can help prevent a tick infestation in your lawn and home.
• Apply the appropriate pesticides to your lawn when necessary. Always read and follow the directions.

For more information about how to protect yourself from ticks, visit the CDC website.

MSU Extension Publication 2331, “Control of Insect Pests In and Around the Home Lawn,” includes information on managing ticks and other pests.

For more information about alpha-gal syndrome, visit the CDC website.