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What is alpha-Gal Syndrome?

Alpha-Gal syndrome, also known as a delayed mammalian (red) meat allergy (and sometimes mistakenly referred to as “alpha-Gal allergy”), is a tick-related allergic reaction to a sugar found in red meats, including beef, pork, venison, and lamb.1,2 In the United States, alpha-Gal syndrome has been primarily connected to a bite from the Lone Star tick (Amblyomma americanum).3,4 This is how it works: First, a bite from a tick can potentially transfer alpha-Gal into a person’s bloodstream. In some of the children and adults bitten, that transfer can cause a production of specific IgE which in turn can cause a delayed allergic reaction after they eat red meat. This means an alpha-Gal reaction can appear suddenly in people who have happily eaten meat for years.5

IgE alpha-Gal Increases

Adapted from Steinke JW, Platts-Mills TA, Commins SP. The alpha-gal story: lessons learned from connecting the dots. J Allergy Clin Immunol. 2015;135(3):589‐597. doi:10.1016/j.jaci.2014.12.1947


Unlike most food allergies, where symptoms often appear within minutes, symptoms of alpha-Gal syndrome are typically delayed by three to six hours or more.6,7 This delay contributes to confusion, as people suffering from the syndrome struggle to connect their reaction to meat consumed hours before. A convenient blood test that measures these antibodies can help your healthcare provider determine if you have alpha-Gal syndrome. 

Symptoms can appear 3 to 6 hours or more after the consumption of red meat.6,7

What are the symptoms of          alpha-gal syndrome?

Common alpha-Gal symptoms include:

  • Itchy skin or hives
  • Swelling of the face
  • Digestive symptoms (e.g., stomach pain, diarrhea, nausea) before the onset of other symptoms
  • Anaphylaxis, a life-threatening reaction

It’s important to note that things such as non-steroidal anti-inflammatory drugs (NSAIDs), exercise, alcohol, and recent tick bites may increase the risk  or severity of reaction.2,10

anaphylaxis is a life threatening reaction


Alpha-Gal allergy symptoms can vary from person to person, but most reactions are skin or stomach-related. Reactions can also range from mild to severe, including the life-threatening reaction, anaphylaxis.1,8,9

Testing icon


The first step to determine the cause of a reaction is to identify allergic triggers. This is especially important because while they are undiagnosed, people with alpha-Gal syndrome are likely to make many trips to the emergency room and visits to their healthcare provider, searching for answers they don’t always get.11 In fact, one study found that almost 80 percent of patients with alpha-Gal syndrome weren’t diagnosed for more than seven years.11

Because alpha-Gal syndrome symptoms may be delayed by hours, it can be hard to associate the symptoms with eating red meat or a product made with mammalian meat (such as gelatin) hours earlier, not to mention relating it to a tick bite in the past. Since this syndrome was only first reported in the late 2000s, many people are unaware of it—including healthcare providers. This has led people to self-diagnosis, but if you think you or a loved one has an alpha-Gal allergy, don’t try to manage the problem on your own.11

So what are your testing options? Your allergist cannot perform skin-prick tests (SPT) directly for alpha-Gal sensitization, making specific IgE blood testing for the alpha-Gal component the preferred diagnostic method.12

A convenient blood test that any provider can order—together with your medical history—can help identify underlying allergic triggers, if you have an allergy. Knowing if you’re allergic and what you’re allergic to may also help you avoid more serious issues in the future. Be sure to consult with your healthcare provider to get detailed answers to your alpha-Gal questions. Because it’s not just knowledge you’ll gain, but peace of mind, too.



The primary advice after an alpha-Gal allergy diagnosis is that all mammalian (red) meats and red meat by-products should be avoided.9 The most common triggers are beef, pork, lamb, but also includes red meats like horse, goat, rabbit, squirrel and venison, plus organ meats.2,17 Some people may also need to avoid dairy products, including milk and cheese, and gelatin-containing foods like marshmallows and jelly candies.2,9 Mammalian by-products including alpha-Gal can also be found in medications, cosmetics, and vaccines which can also cause a reaction.2, 14-17

Not all triggers are equally likely to cause a reaction—see the chart for triggers ranked from higher to lower risk.2

Allergic Trigger Risk
My Symptom Profile

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Talk to your healthcare provider about specific IgE blood testing.

Use these questions to help your healthcare provider understand what’s going on with your symptoms. Review your answers together during your office visit to decide if specific IgE blood testing is right for you.

Help your healthcare provider understand what’s been going on with your symptoms and decide if specific IgE blood testing is right for you!

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Here Is Your Recap. Now What?

What can your My Symptom Profile tell you about allergies? Nothing, by itself. So resist the temptation to self-diagnose. Treating allergy symptoms with over-the-counter medications or other remedies without determining the cause could lead to more issues in the long run. When paired with testing, such as specific IgE blood testing for food or respiratory allergies, your My Symptom Profile can guide your healthcare provider in creating a customized trigger-management plan to help reduce exposure to suspected allergens.

What symptoms are you experiencing or have you experienced?

Do your symptoms get worse during a particular time?

Do you notice your symptoms more in certain places?

How long have your symptoms been present?


Select all that apply
Runny nose
Itchy eyes
Chest tightness
Abdominal cramps
Itchy mouth
Difficulty breathing
Red, itchy patches of skin
Scratchy throat
Select all that apply
In the morning
At nighttime
In the fall
In the spring/summer
In winter or when temperatures drop
After eating certain foods
When sick
During or after exercise
Select all that apply
At home
At school/work
Around pets or animals
Select one
Since birth
Less than 1 week
More than 6 weeks
For several years

Download a PDF of your results to help guide your conversation and maximize your time with your healthcare provider.

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  1. Alpha-gal Allergy [Internet]. Centers for Disease Control and Prevention. Centers for Disease Control and Prevention; 2019. Retrieved June 2020. https://www.cdc.gov/ticks/alpha-gal/index.html
  2. Platts-Mills T, Li R, Keshavarz B, Smith A, Wilson J. Diagnosis and Management of Patients with the α-Gal Syndrome. Journal of Allergy and Clinical Immunology: In Practice. 2020;8(1):15-23.e1.
  3. Wilson JM, Schuyler AJ, Workman L, Gupta M, James HR, Posthumus J, et al. Investigation into the a-Gal Syndrome: Characteristics of 261 Children and Adults Reporting Red Meat Allergy. J Allergy Clin Immunol Pract. Sep-Oct 2019;7(7):2348-2358.
  4. Berg EA, Platts-Mills TA, Commins SP. Drug allergens and food - the cetuximab and galactose-alpha-1,3-galactose story. Ann Allergy Asthma Immunol. 2014 Feb;112(2):97-101.
  5. Steinke JW, Platts-Mills TA, Commins SP. The alpha-gal story: lessons learned from connecting the dots. J Allergy Clin Immunol. 2015;135(3):589‐597. doi:10.1016/j.jaci.2014.12.1947
  6. Commins SP, Satinover SM, Hosen J, Mozena J, Borish L, Lewis BD, et al. Delayed anaphylaxis, angioedema, or urticaria after consumption of red meat in patients with IgE antibodies specific for galactose-alpha-1,3-galactose. J Allergy Clin Immunol. 2009  Feb;123(2):426-33.
  7. Commins SP, Platts-Mills TA. Delayed anaphylaxis to red meat in patients with IgE specific for galactose alpha-1,3-galactose (alpha-gal). Curr Allergy Asthma Rep. 2013  Feb;13(1):72-7.
  8. Kennedy JL, Stallings AP, Platts-Mills TA, Oliveira WM, Workman L, James HR, et al. Galactose-alpha-1,3-galactose and delayed anaphylaxis, angioedema, and urticaria in children. Pediatrics. 2013 May;131(5):e1545-52.
  9. Tripathi A, Commins SP, Heymann PW, Platts-Mills TA. Delayed anaphylaxis to red meat masquerading as idiopathic anaphylaxis. J Allergy Clin Immunol Pract. 2014 May-Jun;2(3):259-65.
  10. Wolbing F, Fischer J, Koberle M, Kaesler S, Biedermann T. About the role and underlying mechanisms of cofactors in anaphylaxis. Allergy. 2013 Sep;68(9):1085-92.
  11. Flaherty MG, Kaplan SJ, Jerath MR. Diagnosis of life-threatening alpha-gal food allergy appears to be patient driven. J Prim Care Community Health. 2017 Oct;8(4):345-348.
  12. Michel S, Scherer K, Heijnen IA, Bircher AJ. Skin prick test and basophil reactivity to cetuximab in patients with IgE to alpha-gal and allergy to red meat. Allergy. 2014 Mar;69(3):403-5.
  13. Macher BA, Galili U. The Galα1, 3Galβ1, 4GlcNAc-R (α-Gal) epitope: a carbohydrate of unique evolution and clinical relevance. Biochimica Biophysica Acta (BBA)-General Subjects. 2008;1780(2):75-88.
  14. Caponetto P, Fischer J, Biedermann T. Gelatin-containing sweets can elicit anaphylaxis in a patient with sensitization to galactose-alpha-1,3-galactose. J Allergy Clin Immunol Pract. 2013 May-Jun;1(3):302-3.
  15. Van Nunen S. Galactose-alpha-1, 3-galactose, mammalian meat and anaphylaxis: a world- wide phenomenon? Curr Treat Options Allergy. 2014;1(3):262-77.
  16. Mullins RJ, James H, Platts-Mills TA, Commins S. The relationship between red meat allergy and sensitization to gelatin and galactose-alpha-1,3-galactose. J Allergy Clin Immunol. 2012 May;129(5):1334-42.
  17. Stone CA, Jr., Hemler JA, Commins SP, et al. Anaphylaxis after zoster vaccine: Implicating alpha-gal allergy as a possible mechanism. J Allergy Clin Immunol. 2017;139(5):1710-1713.e1712.