Alpha-gal allergy in a South Asian country.

Background: Alpha gal syndrome (AGS) is a delayed allergy to red meat, due to IgE to galactose-alpha-1,3-galactose (alpha-gal). Sensitization occurs via tick bites. It has been described in the US, Europe, Australia, Japan and South Korea, but reports from the Indian subcontinent are rare. We report the demographics of alpha-gal allergy for the first time from the Indian subcontinent and possible association with vaccine allergy.

Methods: Patients diagnosed with alpha-gal syndrome (AGS) from 2018 to 2024 were selected in this study. AGS was identified by the occurrence of allergic symptoms up to 8 h of ingestion of red meat, with positive serum IgE to alpha-gal > IgE to red meat, and negative IgE to BSA. Allergy to vaccines containing bovine products were also identified in patients with AGS.

Results: Fifty-seven patients were identified. Thirty-one (54.3%) were 12 years or younger. There were more females among adults (63.2%) compared to children (50.0%), though statistically not significant. There was no difference between children and adults in relation to clinical features and time of onset of symptoms. However, 5/6 of adults with severe anaphylaxis (grade 5) were females. Six patients with AGS developed allergy, including anaphylaxis, to the measles, mumps, rubella (MMR, n = 3), rubella (n = 1), varicella (n = 1) and anti-rabies (n = 1) vaccines.

Conclusion: AGS is an important cause of food and vaccine allergy in the Indian subcontinent and is commoner in children unlike in other regions. However, the clinical features are similar to adults.