Clinicians should consider the possibility of Alpha-gal syndrome in patients with unexplained GI symptoms even in the absence of anaphylaxis, a team from Cairns Hospital has argued.

Dr Elias Bitzer and colleagues shared details of a quality assurance audit at the hospital before and after implementing a clinical guideline for the detection and diagnosis of condition, also known as mammallian meat allergy, finding a gastrointestinal phenotype was both present and likely under-recognised in the region [link here].

Alpha-gal syndrome is an allergy to oligosaccharide galactose-α-1,3-galactose, a carbohydrate found on cells of nonprimate mammals. Acquired via tick bites, patients usually present with anaphylaxis.

But a GI phenotype of the condition has been increasingly described, including abdominal pain, diarrhea, nausea and vomiting 2-6 hours after meat has been ingested.

In their review of patients at Cairns Hospital, the authors found:

• Five out of 19 patients (26%) tested positive for alpha-gal ssIgE sensitisation, 16 in the 12 months before and three in the six months after the guidelines.
• All had GI symptoms, none had anaphylaxis,
• All patients who tested positive had a history of diahhrea, and three had nocturnal symptoms.

Testing yield increased from 12.5% of patients to 100% of those presenting after the clinical guideline was introduced.

“Three of five patients with alpha-gal sensitisation had subsequent review by the time of writing, all with resolution of symptoms post avoidance of mammalian meat,” the authors wrote in JGH Open.

“Early results suggest high correlation of sensitisation to alpha-gal and AGS diagnosis at our centre, supporting the utility of targeted testing for ssIgE to alpha-gal in this population.”

Testing positive for sensitivity to alpha-gal was not enough to diagnose a meat allergy – but must also include a clear improvement in symptoms after stopping the consumption of beef, lamb, pork, dairy and gelatine.

“A thorough history prior to alpha-gal sensitivity testing is strongly advocated to improve the utility of the test,” the authors said.

Overall, the experience at Cairns Hospital supported alpha gal syndrome “being considered in patients with otherwise unexplained gastrointestinal symptoms in tick-endemic regions”, the authors said.

“As the northernmost tertiary gastroenterology service on Australia’s eastern seaboard, these findings extend the recognised distribution of AGS and suggest that the condition may be more prevalent than currently appreciated.”