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How can primary care improve the diagnosis of alpha-Gal syndrome?

Article
Food allergy

Alpha-Gal syndrome, a trigger of red meat allergy

Alpha-Gal syndrome, a red meat allergy, is triggered by IgE antibodies targeting galactose-alpha-1,3-galactose known as “alpha-Gal” found in the meats of non-primate mammals. Tick bites are the primary carrier for this sensitization. Recognizing a potential connection to tick bites can significantly aid the diagnostic process. 1,3

Raw steak on wooden cutting board with fresh herbs

Alpha-Gal clinical manifestations

Alpha-Gal syndrome commonly appears in adolescents and adults, as symptoms range from unexpected urticaria (itchy rash and hives) to gastrointestinal problems (diarrhoea), and, in severe cases, anaphylaxis. Symptoms typically appear 3-6 hours after consuming red meat (like beef, pork, lamb or innards).1-4

Often misdiagnosed as irritable bowel syndrome, there is a significant amount of underdiagnosis, with about 80% of patients experiencing delays of over seven years in receiving an accurate diagnosis. Fortunately, efforts in heightened awareness and enhanced diagnostic methods are fostering a positive shift. This progress holds promise for shorter diagnosis times, providing an improvement in recognizing and managing alpha-Gal allergies.5

The risk and severity of reactions in alpha-Gal syndrome are influenced by the oligosaccharide quantity in food, drugs or therapeutics. Administration route matters, as intravenous exposure triggers rapid reactions, while oral ingestion leads to delayed onset.

Diagnostic approaches

In the case of suspected mammalian meat allergy, a detailed clinical history focusing on predisposing factors such as tick bites, meat consumption and the onset of symptoms, as well as potential cofactors like alcohol consumption, physical activity and the use of nonsteroidal anti-inflammatory drugs, is essential due to the varying reactions among patients.2,7

The employment of specific IgE blood tests, such as the ImmunoCAPTM  Specific IgE test, enhances this analysis by offering a more precise and reliable diagnosis. This approach enables healthcare professionals to develop tailored and effective care strategies for each patient.6,8

In a typical alpha-Gal allergic patient:

  • Diagnosis is supported by IgE to several mammalian meats: pork, beef and lamb.9
  • IgE levels against alpha-Gal are higher compared to IgE against mammalian meats.9, 10

Management consideration

Specific IgE tests results should be interpreted along with patient history, symptoms and physical examination to aid in diagnosis and management plan development.4,6

Learn more about alpha-Gal and ImmunoCAP Specific IgE tests.

Beyond alpha-Gal syndrome: Pork cat syndrome & cow's milk allergen cross-reactivity

It is also important to be aware that there are other types of IgE-mediated meat allergies, such as:

  • Pork-cat syndrome: a rare reaction to pork in individuals sensitized to cat serum albumin, due to cross-reactivity between serum albumins. This involves an immediate IgE response. Diagnosis includes specific IgE tests for pork, cat and cat serum albumin (Fel d 2).11
  • Cow's milk allergen cross-reactivity: 10-20% of children with cow milk allergy may have a cross-allergy to beef or veal due to serum albumin from cow's milk (Bos d 6).12, 13

Specific IgE blood testing can help narrow your differential diagnosis.

You have the power to make a difference.

* Full name of products: ImmunoCAP Allergen e1, Cat dander; ImmunoCAP Allergen e220, component rFel d 2, Cat serum albumin; ImmunoCAP Allergen e204, component nBos d 6, Bovin Serum Albumin

 

 

 


 

 

 

 

 

For additional info on ImmunoCAP testing, allergies, and/or educational tools and resources, contact our allergy experts.

References
  1. Taylor, M. L. et al. Intrinsic risk factors for alpha-gal syndrome in a case-control study, 2019 to 2020. Annals of Allergy, Asthma & Immunology (2024) doi:10.1016/j.anai.2024.01.029.
  2. Steinke, J. W., Platts-Mills, T. A. E. & Commins, S. P. The alpha gal story: Lessons learned from connecting the dots. J Allergy Clin Immunol 135, 589 (2015).
  3. Mayo Clinic [Internet]. Rochester, MN: Mayo Foundation for Medical Education and Research; Available from: https://www.mayoclinic.org/diseases-conditions/alpha-gal-syndrome/symptoms-causes/syc-20428608.
  4. Jackson, W. L. Mammalian meat allergy following a tick bite: a case report. Oxf Med Case Reports 2, 58–60 (2018).
  5. Flaherty, M. G., Kaplan, S. J. & Jerath, M. R. Diagnosis of Life-Threatening Alpha-Gal Food Allergy Appears to Be Patient Driven. J Prim Care Community Health 8, 345–348 (2017).
  6. Platts-Mills, T., Li, R. C., Smith, A. R. & Wilson, J. M. Diagnosis and management of patients with the α-Gal syndrome. J Allergy Clin Immunol Pract. 8(1), 15–23 (2020).
  7. Patel, C. & Iweala, O. I. ‘Doc, will i ever eat steak again?’: Diagnosis and management of alpha-gal syndrome. Current Opinion in Pediatrics vol. 32 816–824 Preprint at https://doi.org/10.1097/MOP.0000000000000955 (2020).
  8. Commins, S. P. Diagnosis & management of alpha-gal syndrome:lessons from 2,500 patients. Expert Rev Clin Immunol 16, 667 (2020).
  9. Commins, S. P. et al. Delayed clinical and ex vivo response to mammalian meat in patients with IgE to galactose-alpha-1,3-galactose. (2014) doi:10.1016/j.jaci.2014.01.024.
  10. Hamsten, C. et al. Red meat allergy in Sweden: Association with tick sensitization and B-negative blood groups. J Allergy Clin Immunol. 132(6), 1431–1434 (2013).
  11. Tedner, S. G. et al. Food allergy and hypersensitivity reactions in children and adults—A review. J Intern Med 291, 283–302 (2022).
  12. García, B. E. & Lizaso, M. T. Cross-reactivity Syndromes in Food Allergy. J Investig Allergol Clin Immunol 21, 162–170 (2011).
  13. Meyer, R. et al. World Allergy Organization (WAO) Diagnosis and Rationale for Action against Cow’s Milk Allergy (DRACMA) Guideline update - VII - Milk elimination and reintroduction in the diagnostic process of cow’s milk allergy. World Allergy Organization Journal 16, 100785 (2023).