What Is an Alpha-Gal Allergy?

An alpha-gal allergy—also referred to as alpha-gal syndrome (AGS)—is an allergic reaction to red meat, such as beef, pork, lamb, or other mammal products.

This condition is most often caused by a tick bite, which transmits a sugar molecule called alpha-gal into the person's body. In some people, this triggers an immune system reaction that later produces mild to severe allergic reactions.

It is believed up to 3% of the population have an alpha-gal allergy, but it's possible there are more misdiagnosed or undiagnosed cases.

This article covers what causes alpha-gal allergy, symptoms, treatment options, prevention strategies, and when to see a healthcare provider.

alpha-gal allergy spelled out with a partial definition

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What Is Alpha-Gal?

Alpha-gal (alpha galactose-1,3-galactose) is a carbohydrate found in the saliva of the lone star tick that has a similar structure to a carbohydrate found in mammalian meat.

Causes

A growing body of research suggests that an alpha-gal allergy may be triggered when a person is bitten by a specific species of tick called the lone star tick. The role of tick bites in the development of alpha-gal allergy is not yet fully understood.

Symptoms

An allergic reaction will not always occur following exposure to alpha-gal, and the reaction from alpha-gal can vary between people.

The average delay in reaction time is between two to six hours. But this can vary from just minutes to as long as 12 to 24 hours.

An alpha-gal allergy presents much later than most other food allergies, which typically occur within 20 to 30 minutes.

An alpha-gal reaction may cause symptoms like:

  • Nausea
  • Vomiting
  • Rash
  • Diarrhea
  • Hives
  • Indigestion
  • Shortness of breath
  • Trouble breathing
  • Fainting
  • Dizziness
  • Cough
  • Swollen lips, tongue, throat, or eyelids
  • Drop in blood pressure
  • Heartburn
  • Stomach pain that is severe

Testing for an Alpha-gal Allergy

Alpha-gal allergy is typically diagnosed through a combination of:

  • Medical history
  • Physical exam
  • Blood tests

The blood tests help to find alpha-gal antibodies that are created by the immune system. In some cases, a healthcare provider may also undertake an allergy skin test.


When to See a Healthcare Provider

If you suspect you might have an alpha-gal allergy, you should contact your healthcare provider.

Alpha-gal allergy can be serious and potentially life-threatening, as it can cause anaphylaxis, which warrants immediate medical attention.

If you suspect you are experiencing a severe reaction, immediately see a healthcare provider.

Anaphylaxis Is a Medical Emergency

If you're with someone you suspect is in anaphylaxis, it's important you act quickly.

You should:

  • Use an EpiPen on the person if they have one.
  • Call an ambulance, even if the person says they feel better.
  • If possible, have the person lie down and raise their legs.
  • If the person is having problems breathing, sit them up to help them breathe.
  • If the person is pregnant, have them lie down on their left-hand side.
  • If possible and a second EpiPen is available, give a second shot after five minutes if symptoms do not get better.




Treatment

Treatment for alpha-gall allergy is typically through an allergist and other healthcare providers.

Avoiding further tick bites is important.

Treating allergic reactions may involve:

In severe allergic reactions like anaphylaxis, adrenaline is used.

Those who are diagnosed with an alpha-gal allergy will usually be asked to not eat red meat. This includes:

  • Beef
  • Lamb
  • Pork
  • Venison

In some cases, it may also be necessary to avoid other foods and products that contain alpha-gal. This includes things like:

  • Gelatin
  • Cow's milk
  • Milk products

Chicken and fish may still be eaten.

Alpha-gal can be present in some medications and vaccinations. It is important that those with an alpha-gal allergy speak with a healthcare provider before having a new medication or vaccination.

Prevention

The main prevention strategy for avoiding alpha-gal allergy is to avoid tick bites.

In the United States, contact with ticks can happen any time of year but is most common from April to September when the weather is warmer.

Ticks can be found in a number of places outdoors including:

  • Wooded areas
  • Brushy areas
  • Areas with grass

Ticks can also be found on animals. Being outside in the yard or walking the dog can potentially expose a person to ticks.

There are some simple strategies for trying to avoid tick bites when outside:

  • Use insect repellant.
  • Treat clothing or camping gear with 0.5% permethrin.
  • Try to walk in the center of walking trails.
  • Where possible, avoid areas that are wooded or brushy or that contain a lot of litter from leaves and grass.

There are also ways to prevent tick bites once returning indoors. These include:

  • Examining clothing for ticks. If ticks are found on clothing, they should be removed. Using a tumble dryer for 10 minutes will help kill ticks.
  • Checks pets for ticks.
  • Take a shower within two hours of returning indoors. According to the Center for Disease Control and Prevention (CDC), this has been proven to reduce the risk of tickborne diseases.

Checking the body for ticks after being outside is another important prevention strategy. This can involve standing in front of a mirror or using a handheld mirror to search for ticks. Remember to check:

  • The belly button
  • Around the ears
  • Under the arms
  • Behind the knees
  • In the hair
  • Between legs

Summary

An alpha-gal allergy is a delayed allergic reaction to red meat that is triggered by a tick bite. It may also cause an immediate reaction to medications containing the alpha-gal molecule.

The most effective method of preventing alpha-gal allergy is to avoid tick bites.

A Word From Verywell

A delayed allergic reaction to red meat could be distressing and come as a shock. If you suspect you may have an alpha-gal allergy, it is important to speak with a healthcare provider for advice. They will be able to support you in making changes like cutting out red meat and devising strategies to avoid future tick bites.

Frequently Asked Questions

  • What foods should you avoid if you have an alpha-gal allergy?

    Those with an alpha-gal allergy should avoid red meat and products that contain alpha-gal. This can include things like gelatin and cow's milk.

  • Can an alpha-gal allergy go away?

    More research is needed to better understand the long-term implications of alpha-gal allergy. It's possible in some people it may be transient and may eventually go away after 18 months or two years. At that time, it may be possible to attempt to reintroduce red meat.

  • Where are alpha-gal allergies most common?

    In the United States, alpha-gal allergy has been reported in the South, East, and Central parts of the country. It has also been reported all over the world.

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8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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