D3.64 - Alcohol-Soluble Wheat Proteins as the Likely Allergenic Trigger in a Patient With Reaction to Gin

Allergic reactions to distilled alcoholic beverages are uncommon, as distillation typically removes most protein content; however, residual or alcohol-soluble proteins may persist and become clinically relevant in sensitized individuals. Distillation matrices incorporating cereals, herbs or botanicals can selectively enrich proteins with increased solubility in alcohol, sometimes unmasking allergens absent in the parent food. We report a patient with reproducible oral pruritus and generalized itching after gin consumption, in whom detailed molecular testing was required to identify the allergenic origin.

A 69-year-old man with seasonal rhinitis to Cupressaceae and mild oral allergy syndrome to kiwi, mango and certain dairy desserts reported reproducible itching after gin ingestion. Skin prick tests were positive to Cupressus arizonica, Parietaria, horse dander, mosquito and kiwi. Specific IgE included Cupressus arizonica 8.78 kU/L, Platanus acerifolia 1.91 kU/L, Vespula spp. 35.7 kU/L and Polistes dominula 2.57 kU/L.Protein extracts were prepared from juniper berries, Cupressus arizonica pollen, Juniperus oxycedrus pollen and wheat flour (aqueous and alcohol-soluble fractions). Alcohol-soluble proteins were extracted with 55% 2-propanol + 1% 2-mercaptoethanol. SDS-PAGE and IgE–Western blot were performed under reducing conditions. An IgE-ELISA with juniper berry extract and an inhibition analysis with milk were included.

SDS-PAGE showed markedly different proteomic patterns between juniper, Cupressaceae pollens and wheat fractions. IgE–Western blot demonstrated no IgE binding to juniper berries, confirmed by a negative ELISA, excluding juniper as the trigger. Cupressaceae pollens displayed IgE binding to a ~40 kDa pectate-lyase band, consistent with the patient’s airborne sensitization but unrelated to gin reactions. In contrast, the alcohol-soluble wheat fraction exhibited a distinct IgE-reactive band at ~40 kDa, compatible with low-molecular-weight glutenins (Tri a 36), whereas the aqueous wheat extract showed no IgE binding. The selective recognition of alcohol-soluble wheat proteins, combined with the patient’s tolerance to wheat-based foods, indicates that alcohol extraction during gin production exposes allergenic epitopes that are absent or non-reactive in native wheat.

The findings indicate that the patient’s reaction to gin is best explained by IgE sensitization to alcohol-soluble wheat proteins, rather than juniper or Cupressaceae components. This case illustrates how processing and alcohol extraction can unmask clinically relevant allergens undetectable by standard IgE testing, reinforcing the value of molecular diagnostics in complex food-beverage reactions.