Otolaryngology Book

Immunologic Disorders

Parasitic Infections


Alpha Gal Reaction

Aka: Alpha Gal Reaction, Alpha-Gal Reaction, Alpha-Gal Allergy, Alpha-Gal Syndrome, Red Meat Allergy
  1. Mechanism
    1. Occurs after Lone Star Tick Bite (Amblyomma Americanum), found in the eastern and southeastern United States
    2. Sensitization to Galactose-alpha-1,3-galactose (alpha-gal) due to IgE cross reactivity
    3. Alpha-gal is present in both tick Saliva and red meat (lamb, pork, beef, venison, rabbit)
  2. Findings
    1. New severe, sudden, Allergic Reaction (Urticaria, Anaphylaxis) to red meat (beef, lamb, pork, venison, rabbit)
  3. Associated Conditions: Other Lone Star Tick related illnesses
    1. Tularemia
    2. Ehrlichiosis
    3. Heartland Virus
    4. Bourbon Virus
    5. Southern Tick Associated Rash Illness (STARI)
  4. Findings
    1. Allergic Reaction onset 2 to 6 hours after red meat (or derived product) ingestion
  5. Differential Diagnosis: Red Meat Allergy
    1. Alpha-Gal Syndrome (described on this page)
    2. Primary Beef Allergy
      1. Young children with Atopic Dermatitis (esp. with Cow's Milk Allergy)
    3. Pork-Cat Syndrome
      1. Patients with cat allergy develop pork allergy (and in some cases beef allergy)
      2. Primarily seen in teens and young adults
  6. Management
    1. See Allergic Reaction
    2. See Anaphylaxis
    3. Avoid all red meat products
    4. Avoid animal derived products (e.g. cow's milk, gelatin)
  7. Prevention
    1. See Prevention of Vector-borne Infection
  8. Resources: Patients
    1. Alpha-Gal (Mayo Clinic)
      1. https://www.mayoclinic.org/diseases-conditions/alpha-gal-syndrome/symptoms-causes/syc-20428608
    2. Alpha-Gal (CDC)
      1. https://www.cdc.gov/ticks/alpha-gal/index.html
  9. References
    1. Commins (2011) J Allergy Clin Immunol 127(5): 1286-93 [PubMed]
    2. Wilson (2019) Curr Opin Allergy Clin Immunol 19(3):229-35 +PMID: 30844847 [PubMed]

Allergy to red meat (C1630645)

Concepts Pathologic Function (T046)
SnomedCT 418815008
Spanish alergia a las carnes rojas (trastorno), alergia a las carnes rojas
English Allergy to red meat (disorder), Allergy to red meat
Derived from the NIH UMLS (Unified Medical Language System)

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