Spectrum of symptoms observed in patients with alpha-gal syndrome
Click Here to Manage Email Alerts
Symptoms ranging from minor to life-threatening were reported in a single-site study of patients with alpha-gal syndrome, according to a poster presented at the American College of Allergy, Asthma & Immunology Annual Scientific Meeting.
“Humans have recently been recognized as having severe delayed hypersensitivity reactions consequent to ingestion of alpha-gal-containing foods in the form of mammalian meat products (ie, beef and pork),” Lawrence P. Landwehr, MD, of Allergy & Asthma Consultants in central Missouri, and colleagues wrote, adding that sensitization is thought to occur via tick bites from the Lone Star tick, which is commonly found in Missouri.
“The hypersensitivity response presents itself in an array of symptoms ranging from minor skin reactions to life-threatening anaphylaxis," they added. "Our goal was to explore symptoms experienced by those diagnosed with an alpha-gal allergy in a Missouri practice.”
In a retrospective chart review, researchers evaluated 70 patients (54% women; mean age, 50.4 years; mean alpha-gal IgE, 17.6 kU/L) who were diagnosed with alpha-gal syndrome between the years 2013 to 2019.
Of these patients, 42 underwent testing for serum IgE to beef and pork. Researchers found that 31 out of the 42 patients tested positive (IgE > 0.1 kU/L) for serum IgE to beef, and 30 tested positive for pork. There were 37 patients who underwent a skin prick test to beef and pork, with 11 testing positive for beef and 11 testing positive for pork.
Out of 70 individuals, 44 (mean alpha-gal IgE, 18.9 kU/L) were found to have histories and/or objective findings consistent with anaphylaxis. These subjects reported skin involvement in addition to respiratory symptoms (n = 30), cardiovascular symptoms (n = 13) and/or gastrointestinal symptoms (n = 23). Of this group, 35 patients reported emergency room care, and three were hospitalized.
A second group, defined by having “skin-only symptoms” such as pruritus, urticaria, and/or angioedema without evidence of systemic symptoms, included 26 individuals with a mean alpha-gal IgE of 13.6 kU/L.
Four patients reported complete allergy resolution while two then underwent subsequent negative office challenges to meat. In all subjects, symptom onset was found to occur 3 to 6 hours after ingestion. Other reported triggers were milk (n = 8), venison (n = 4), gelatin containing medication (n = 4) and lamb (n = 2).
“Alpha-gal hypersensitivity is a serious medical concern as demonstrated [by] these 68 patients diagnosed in this mostly rural practice in Central Missouri over a 6-year period,” the researchers wrote. “Our report emphasizes the importance of considering alpha gal sensitivity in patients presenting with varying allergic symptoms in absence of immediate allergen association.”