Alpha-gal Syndrome

Alpha-gal syndrome is an allergic condition that can develop after the bite of certain ticks carrying a sugar molecule called alpha-gal. Alpha‑gal syndrome is sometimes referred to as a red meat allergy or mammalian meat allergy because the resulting allergy may sensitize the immune system to meat in some people.  When an exposed person eats most mammalian meat, their body reacts to the molecule which cascades into immune pathways resulting in an allergic reaction.

Lone star ticks (Amblyomma americanum) are the primary transmitters of alpha-gal. Blacklegged ticks, or deer ticks (Ixodes scapularis), have also been investigated as possible contributors in a small number of reported cases.

Alpha-gal is most commonly transmitted by the bite of a lone star tick.

In the US, Alpha-gal syndrome is most common in Central and Eastern States. The syndrome can be difficult to diagnose, and not all states have mandated reporting. This makes accurate incidence numbers difficult to determine. Alpha-gal syndrome cases are expected to increase as lone star ticks expand their range northwards into New England and the Midwest.

U.S. geographic distribution of suspected alpha-gal syndrome cases per 1M population (2017–2022), Thompson JM, Carpenter A, Kersh GJ, Wachs T, Commins SP, Salzer JS. Morb Mortal Wkly Rep 2023; 72:815–820, avail. at: http://dx.doi.org/10.15585/mmwr.mm7230a2. (Used for educational purposes).

• A key feature of Alpha‑gal syndrome are the allergic reactions that may occur several hours after consuming red meat. The delay in symptoms can range from 2-6 hours after eating red meat. In some highly sensitized individuals, reactions have also been reported after exposure to certain mammalian‑derived ingredients, such as gelatin or dairy.
• Common signs and symptoms include:
  • hives or an itchy rash
  • swelling in the face (eyelids, lips, tongue)
  • dizziness or faintness
  • severe stomach pain
  • difficulty breathing
• In severe cases, the individual can develop anaphylaxis.

This information is educational only and does not replace medical advice. Consult a healthcare professional for diagnosis or treatment.

The best way to avoid developing Alpha-gal syndrome is to prevent bites from ticks. The U.S. Centers for Disease Control and Protection recommend preventing tick bites by knowing where ticks will be in the environment, avoiding potential contact with ticks, and by using an Environmental Protection Agency (EPA)-registered insect repellent. Neither the Centers for Disease Control and Prevention or the U.S. Environmental Protection Agency recommend or endorse any specific product, brand or manufacturer.

Sources:

https://www.cdc.gov/alpha-gal-syndrome/about/index.html
https://utia.tennessee.edu/publications/wp-content/uploads/sites/269/2026/04/W1388.pdf
https://www.cdc.gov/mmwr/volumes/72/wr/mm7230a2.htm

You can prevent developing Alpha-gal syndrome by avoiding bites from ticks.

• Know when you may be at a high risk for tick encounters such as hiking, camping, hunting, walking through tall grass, doing yardwork, or mowing the grass.
• Wear personal insect repellent with tick repellency listed on the label In these instances. Always follow usage instructions.
• Applying an EPA registered repellent according to label instructions on your shoes, socks, and pants can also be an effective method to prevent ticks from crawling onto you.

• Applying a personal repellent correctly can help protect you from ticks and mosquitoes. Before using a personal repellent, always read the product label to make sure you are using the product that’s right for you and your family. Always follow the manufacturer’s instructions provided on the repellent you choose.
• If you plan to wear sunscreen, apply sunscreen first and then insect repellent over it.

• First, ensure that your selection of repellent has ticks listed on the label.
• There are many EPA-registered active ingredients to select from when choosing your repellent. Two of these ingredients are DEET and Picaridin. Neither the Centers for Disease Control and Prevention or the U.S. Environmental Protection Agency recommend or endorse any specific product, brand or manufacturer.
  • DEET is used in many registered personal insect repellents for direct application to the skin and can be used on both adults and children when used as directed by the label.
  • Picaridin is another active ingredient in personal repellents. This ingredient is an odorless, colorless and non-greasy liquid that can repel ticks and mosquitoes. Personal repellents with Picaridin do not dissolve plastics or acrylics, making them well suited for various recreational gears and certain clothing.

Source: https://www.cdc.gov/ticks/prevention/index.html