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alpha-gal syndrome

Etiology: - lone star tick Epidemiology: - see lone star tick - suspected cases predominantly occurred in counties within the southern, midwestern, & mid-Atlantic U.S. [2] Pathology: - developmennt of allergy to galactose-alpha-1,3-galactose (alpha-gal) - tick saliva may contain alpha-gal obtained from other mammals on which the tick has fed - exposure to alpha-gal containing tick saliva then triggers development of alpha-gal specific IgE antibodies in humans - once sensitized, consumption of red meat triggers hypersensitivity Clinical manifestations: - most common: - pruritus or urticaria (70%) - gastrointestinal symptoms (40%) - angioedema - contact urticaria of the oral mucosa - anaphylaxis - other - presyncope or syncope - symptoms are delayed in onset, often 3-6 hours after eating* - patients have awakened from sleep with allergic symptoms or anaphylaxis after eating red meat for dinner * carbohydrate alpha-gal is bound to lipid * lipids are absorbed into the gut and circulation more slowly than proteins Laboratory: - alpha-gal IgE in serum/plasma >= 0.1 IU/mL (confirmatory) Management: - supportive care - no treatment of cure available [3]

Related

Amblyomma americanum (Lone Star tick) galactose

General

tick-related allergy syndrome

References

  1. Rothaus C Hunting for a Diagnosis NEJM Resident 360. Feb 3, 2021 https://resident360.nejm.org/clinical-pearls/hunting-for-a-diagnosis
  2. Thompson JM, Carpenter A, Kersh GJ, Wachs T, Commins SP, Salzer JS. Geographic Distribution of Suspected Alpha-gal Syndrome Cases - United States, January 2017-December 2022. MMWR Morb Mortal Wkly Rep 2023;72:815-820. Jyly 28. PMID: 37498787 https://www.cdc.gov/mmwr/volumes/72/wr/mm7230a2.htm
  3. Carpenter A, Drexler NA, McCormick DW, et al. Health Care Provider Knowledge Regarding Alpha-gal Syndrome - United States, March-May 2022. MMWR Morb Mortal Wkly Rep 2023;72:809-814. July 28 PMID: 37498792 https://www.cdc.gov/mmwr/volumes/72/wr/mm7230a1.htm
  4. Centers for Disease Control & Prevention (CDC) Alpha-gal Syndrome (AGS) 2022 Case Definition https://ndc.services.cdc.gov/case-definitions/alpha-gal-syndrome-ags/