Sensitivity and specificity of a shortened elimination diet protocol for the diagnosis of food-induced atopic dermatitis (FIAD).

Background: The gold standard to diagnose food allergy in dogs is an eight week elimination diet trial (EDT) followed by a re-challenge. A recent study demonstrated that a shorter EDT is possible if prednisolone is administered initially.

Hypothesis/objectives: The goal was to evaluate the sensitivity and specificity of the EDT based on the number of relapses after prednisolone discontinuation. In addition, the aim was to determine whether the initial treatment length or the replacement of prednisolone with oclacitinib would influence the outcome.

Animals: Eighty-seven dogs with atopic dermatitis.

Methods And Materials: Dogs were fed an elimination diet and treated with either prednisolone or oclacitinib for two to three weeks. Relapsing dogs were treated a second time. In the absence of a relapse after two weeks off medication, dogs then were challenged. Dogs never achieving two weeks off treatment without relapse received the regular EDT.

Results: Fifty-eight of 87 dogs completed the study. Thirty-nine of 58 dogs received prednisolone; 21 of these were diagnosed with FIAD and had no relapse (n = 14), one relapse (n = 6) or two relapses (n = 1). Nineteen of 58 dogs received oclacitinib; 11 of these were deemed food-allergic and had no relapse (n = 7) or two relapses (n = 4). The initial treatment duration did not influence the outcome. The threshold of one relapse or less for the diagnosis of FIAD was associated with a sensitivity of 95% for prednisolone and 63% for oclacitinib. The specificity was 100% for both drugs.

Conclusion And Clinical Importance: Initial prednisolone or oclacitinib use in EDT shortens the time to diagnosis of FIAD.