Allergies
Explore This Topic

What Is Alpha-Gal Syndrome, the Red Meat Allergy Caused by Tick Bites?

What Is Alpha-Gal Syndrome, the Red Meat Allergy Caused by Tick Bites?
iStock; Canva
By
Updated on April 2, 2025
by

Alpha-gal syndrome is the name for a red meat allergy that develops after a tick bite.

Alpha-gal syndrome is rare. But as climate change leads to warmer winters and longer, hotter summers, tick populations are growing and spreading to new areas, increasing the threat of all tick-borne illnesses, including alpha-gal.

Overview

What Is Alpha-Gal Syndrome?

Alpha-gal syndrome (AGS) is a tick-borne condition in which people become allergic to galactose-α-1,3-galactose, also known as alpha-gal, a sugar found in the tissues of most mammals except for humans and primates.

It’s also called mammalian meat allergy, alpha-gal allergy, red meat allergy, and tick bite meat allergy.

Symptoms of alpha-gal syndrome can range from mild to severe. There is no cure but the syndrome often goes away or improves on its own within a year or two.

Signs and Symptoms of Alpha-Gal Syndrome

Symptoms of alpha-gal typically occur two to six hours after red meat is consumed and include:

  • Nausea
  • Diarrhea
  • Heartburn
  • Hives
  • Vomiting
  • Abdominal cramps and pain
  • Bloating
  • Constipation
  • Anaphylactic shock (a potentially deadly reaction)

Women are more likely than men to report gastrointestinal symptoms, and nearly half of AGS patients experience at least one gastrointestinal symptom.

Many people with alpha-gal don’t have a reaction every time they eat red meat.

Causes and Risk Factors of Alpha-Gal Syndrome

Scientists are still working to better understand alpha-gal syndrome, but they have identified a few factors that increase risk.

Tick Bites In the United States, alpha-gal syndrome is primarily caused by the lone star tick, which can transfer the alpha-gal sugar molecule into the body. Some people have a strong immune response to these molecules and develop antibodies against them, leading to allergic reactions when eating red meat. Alpha-gal syndrome is more common in areas where lone star ticks are prevalent, such as the southeastern United States and parts of the mid-Atlantic.

But because of the increasing prevalence of AGS beyond these areas, experts suspect that the syndrome could be caused by bites from other types of ticks, or by chiggers, a close relative of the tick.

The Centers for Disease Control and Prevention (CDC) recently reported two cases of alpha-gal not caused by the lone star tick: one linked to a western black-legged tick, the second linked to a black-legged tick.

Outdoor Activities Spending time outdoors, especially near woodland areas, increases the likelihood of developing alpha-gal syndrome.

Age People of any age can develop alpha-gal syndrome, but most cases have been in adults.

How Is Alpha-Gal Syndrome Diagnosed?

Alpha-gal syndrome is diagnosed by:

  • A physical exam
  • A detailed patient history, including a thorough history of symptoms
  • An immunoglobulin E test (IgE) to detect the allergic antibody
  • In some cases, allergy skin testing
AGS can be difficult to diagnose because some people who have it may not react to red meat every single time they eat it. It is often misdiagnosed as GI conditions like irritable bowel syndrome (IBS).

Treatment and Medication Options for Alpha-Gal Syndrome

There isn’t a cure for alpha-gal syndrome but there are ways to minimize symptoms.

Allergy Medications

Antihistamines can help people with mild reactions to eating red meat. Severe allergic reactions, such as anaphylaxis, may require epinephrine.

Oral cromolyn solution may help with gastrointestinal symptoms.

Dietary Changes

This is the primary way of minimizing alpha-gal symptoms.

Avoid red meat and mammalian products. This is crucial to prevent allergic reactions. This includes cutting out beef, pork, lamb, venison, goat, and rabbit.

Avoid dairy products. Dairy products also contain the alpha-gal sugar, though at lower levels than meat. An estimated 5 to 20 percent of people with alpha-gal have allergic reactions to dairy. In people whose alpha-gal symptoms are not adequately controlled through meat avoidance alone, cutting out dairy may be necessary.

Avoid gelatin. A small percentage of people with alpha-gal syndrome may have to limit foods that contain gelatin, an animal product, such as marshmallows, jelly beans, and Jell-O.

Medication Avoidance

Many medications contain ingredients derived from mammals. People with alpha-gal syndrome should avoid these medications and medical products:

  • Cetuximab (a chemotherapy drug)
  • Gelatin-based colloid plasma substitute (used to treat hypovolemia, a condition in which there is a decrease in the volume of blood circulating in the body)
  • Thyroid hormone supplements derived from cows or pigs
  • Anti-snake venom therapy derived from horses or sheep

A small number of people with AGS may need to additionally avoid the following animal-derived products:

  • Heparin (a blood thinner)
  • Pancreatic enzymes (derived from pigs)
  • Gel capsules
  • Vaccines that contain gelatin (such as the measles, mumps, and rubella [MMR] and yellow fever vaccines)
  • Prosthetic heart valves from cows or pigs

Prevention of Alpha-Gal Syndrome

Tick bite prevention is the best way to avoid getting alpha-gal.

Avoid ticks when possible. Don’t go off trails in wooded and grassy areas.

Use insect repellant with at least 20 percent DEET. Apply permethrin products to clothing, or buy pretreated clothing.

Check for ticks after outdoor activities, and if you have one, remove it immediately, using tweezers to grab the tick near its head or mouth.

Wear protective clothing like long sleeves. Tuck socks into shoes and pants.

How Long Does Alpha-Gal Syndrome Last?

Alpha-gal syndrome can persist for years, but symptoms may improve or even go away entirely over time. Some people with alpha-gal syndrome can eat mammal food products again after one or two years, especially if they don’t get any more tick bites. The condition can return if a person is bitten again by a tick.

The overall outlook for alpha-gal syndrome is good if you follow your treatment plan and your health provider’s recommendations.

How Many People Have Alpha-Gal Syndrome?

Awareness of alpha-gal syndrome has grown in the past decade, but it can still be hard to diagnose, and so many cases might be missed. It’s estimated that between 96,000 and 450,000 people in the United States have been affected by AGS since 2010.

The Takeaway

  • Alpha-gal syndrome is a rare but serious allergy triggered by tick bites that can cause severe reactions to red meat and other mammalian foods.
  • There is no cure for AGS, but people can minimize symptoms by avoiding mammalian meat and other foods and medicines derived from animal products.
  • Prevent tick bites and alpha-gal infection by using bug repellents, avoiding outside activities in areas where ticks thrive, and checking for and removing ticks as soon as possible.
  • If you suspect you have alpha-gal syndrome, it’s essential to get tested by an allergist and eliminate red meat from your diet to manage symptoms.

Common Questions & Answers

What are the most common symptoms of alpha-gal syndrome?
The most common symptom is a delayed reaction to eating red meat, such as nausea, diarrhea, hives, and in severe cases, anaphylaxis, typically occurring two to six hours after eating.
Currently, there is no cure for alpha-gal. The primary treatment is to avoid red meat and other mammalian products.
Alpha-gal is diagnosed through a combination of patient history, symptom evaluation, and blood tests that check for an allergic response to the alpha-gal sugar molecule.
Red meat allergy can improve or go away completely within a year or two if the person avoids additional tick bites.
Alpha-gal syndrome is relatively rare, but recent studies estimate that as many as 450,000 people in the United States could be affected.

Resources We Trust

Cleveland Clinic: Alpha-Gal Syndrome

Centers for Disease Control and Prevention: Products That May Contain Alpha-Gal

Yale Medicine: Alpha-Gal Syndrome

United States Environmental Protection Agency: Tips to Prevent Tick Bites

American Gastroenterological Association: Diagnosis and Management of Alpha-Gal Syndrome

EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Alpha-Gal Syndrome: When a Tick Bite Turns to a Meat Allergy. American Society for Microbiology. December 15, 2023.
  2. Alpha-Gal Syndrome. Cleveland Clinic. December 2, 2022.
  3. Lesmana E et al. Clinical Presentation and Outcomes of Alpha-gal Syndrome. Clinical Gastroenterology and Hepatology. January 2025.
  4. Butler WK et al. Onset of Alpha-Gal Syndrome after Tick Bite, Washington, USA. Emerging Infectious Diseases. Volume 31, Number 4. April 2025.
  5. Saunders EF. Alpha-Gal Syndrome after Ixodes scapularis Tick Bite and Statewide Surveillance, Maine, USA, 2014–2023. Emerging Infectious Diseases. Volume 31, Number 4—April 2025. April 2025.
  6. Alpha-Gal Syndrome. Centers for Disease Control and Prevention. May 15, 2024.
  7. Alpha-Gal Syndrome: Diagnosis & Treatment. Mayo Clinic. November 15, 2022.
  8. Lesmana E et al.  Clinical Presentation and Outcomes of Alpha-Gal Syndrome. Clinical Gastroenterology and Hepatology. January 2025.
  9. Alpha-Gal Syndrome (AGS). Yale Medicine. October 5, 2023.
  10. Alpha-Gal Syndrome: Overview. Mayo Clinic. November 15, 2022.
  11. Alpha-Gal Syndrome. Mayo Clinic. November 15, 2022.
  12. Thompson JM et al. Geographic Distribution of Suspected Alpha-gal Syndrome Cases-United States, January 2017-December 2022. CDC Morbidity and Mortality Weekly Report. July 28, 2023.
Meet Our Experts
See Our Editorial PolicyMeet Our Health Expert Network
jane-yoon-scott-bio

Jane Yoon Scott, MD

Medical Reviewer

Jane Yoon Scott, MD, is an infectious disease physician and an assistant professor of medicine at Emory University in Atlanta. Dr. Scott enjoys connecting with her patients, empowering them to understand and take ownership of their health, and encouraging them to ask questions so that they can make informed and thoughtful decisions.

She graduated with the highest honors from the Georgia Institute of Technology, then received her MD from the Medical College of Georgia. She completed her internal medicine residency training and chief residency at Temple University Hospital, as well as a fellowship in infectious diseases at Emory University. She is board-certified in both internal medicine and infectious diseases.

When she is not seeing patients, Dr. Scott works with neighboring health departments to promote public health, especially to communities that have been historically underserved. She also teaches medical trainees and lectures medical students at the Emory University School of Medicine.

In her free time, Dr. Scott appreciates a good coffee shop, weekend hikes, playing guitar, strolling through cities, sampling restaurants, and traveling to new places.

See full bio
Becky Upham, MA

Becky Upham

Author

Becky Upham has been professionally involved in health and wellness for almost 20 years. She's been a race director, a recruiter for Team in Training for the Leukemia & Lymphoma Society, a salesperson for a major pharmaceutical company, a blogger for Moogfest, a communications manager for Mission Health, a fitness instructor, and a health coach.

She majored in English at the University of North Carolina and has a master's in English writing from Hollins University.

Upham enjoys teaching cycling classes, running, reading fiction, and making playlists.

See full bio
See Our Editorial PolicyMeet Our Health Expert Network
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Alpha-Gal Syndrome: When a Tick Bite Turns to a Meat Allergy. American Society for Microbiology. December 15, 2023.
  2. Alpha-Gal Syndrome. Cleveland Clinic. December 2, 2022.
  3. Lesmana E et al. Clinical Presentation and Outcomes of Alpha-gal Syndrome. Clinical Gastroenterology and Hepatology. January 2025.
  4. Butler WK et al. Onset of Alpha-Gal Syndrome after Tick Bite, Washington, USA. Emerging Infectious Diseases. Volume 31, Number 4. April 2025.
  5. Saunders EF. Alpha-Gal Syndrome after Ixodes scapularis Tick Bite and Statewide Surveillance, Maine, USA, 2014–2023. Emerging Infectious Diseases. Volume 31, Number 4—April 2025. April 2025.
  6. Alpha-Gal Syndrome. Centers for Disease Control and Prevention. May 15, 2024.
  7. Alpha-Gal Syndrome: Diagnosis & Treatment. Mayo Clinic. November 15, 2022.
  8. Lesmana E et al.  Clinical Presentation and Outcomes of Alpha-Gal Syndrome. Clinical Gastroenterology and Hepatology. January 2025.
  9. Alpha-Gal Syndrome (AGS). Yale Medicine. October 5, 2023.
  10. Alpha-Gal Syndrome: Overview. Mayo Clinic. November 15, 2022.
  11. Alpha-Gal Syndrome. Mayo Clinic. November 15, 2022.
  12. Thompson JM et al. Geographic Distribution of Suspected Alpha-gal Syndrome Cases-United States, January 2017-December 2022. CDC Morbidity and Mortality Weekly Report. July 28, 2023.