Predominantly rapid reactions to pork challenge and food-specific IgE patterns in dogs with adverse food reactions

The clinical timing and immune responses associated with challenge-confirmed pork allergy in dogs remain poorly defined. We characterized reactions during veterinarian-supervised oral pork provocation, examined immune responses associated with challenge outcome, and evaluated pork-specific IgE within the broader pattern of food-specific IgE reactivity. In a retrospective study, clinical records and archived serum samples from 136 dogs with adverse food reactions were analyzed. Of 31 dogs undergoing oral pork provocation, 10 were challenge-positive and 21 were challenge-negative. Seven of the 10 positive dogs reacted within 10 min, one additional dog reacted at 2 h, and the remaining two reacted after 2 and 3 days. All 10 challenge-positive dogs developed pruritus, four developed erythema, and the two dogs with delayed reactions developed diarrhea. In-house pork-specific IgE reactivity was higher in challenge-positive dogs than in challenge-negative dogs and healthy controls (q = 0.0397 and 0.0239, respectively), whereas pork-induced lymphocyte proliferation did not differ among groups. Both delayed cases showed pork-specific IgE reactivity near the lower end of the challenge-positive group. Of the two delayed cases, the one with available lymphocyte proliferation data had the highest value among the five challenge-positive dogs. These observations were descriptive because only two delayed cases were identified. Across the broader cohort, principal component analysis of commercial IgE measurements against 18 foods identified a dominant component explaining 55.96% of the total variance. Commercial pork-specific IgE concentrations correlated with IgE concentrations against all 17 other foods. Associations with chicken, egg white, and rice were reproduced using the in-house assay with independently prepared food extracts, whereas the pork–cod association was not. Selected additional food challenges documented clinical multi-food reactivity in some pork-challenge-positive dogs. Challenge-confirmed pork allergy in this cohort was predominantly characterized by rapid reactions and increased pork-specific IgE reactivity. The two delayed cases had clinical and immunological features suggesting possible heterogeneity, although their small number precluded formal comparison. Broader food-specific IgE covariance and additional food-challenge responses provided complementary serological and clinical context.