Investigation of the diagnostic performance of prick test with two environmental allergens in dogs with atopic dermatitis: A study using intradermal test as the gold standard

Background There are no studies investigating the correlation between prick test (PT) and intradermal test (IDT) with environmental allergens in dogs with atopic dermatitis (AD). Objectives To investigate the correlation between PT and IDT for two environmental allergens, and to calculate the sensitivity, specificity and Youden index of PT, using IDT as the gold standard. Materials and methods Twenty‐two dogs with AD were selected. PT was performed with glycerinated allergen extracts, along with negative and positive controls, using the Greer Prick System. Reactions were interpreted (positive/negative) subjectively and by using seven objective criteria, by an examiner blinded to the IDT results. IDT reactions to the same allergens were interpreted, subjectively and objectively, by another masked investigator. The agreement between PT and IDT, the sensitivity, specificity and Youden index of PT, using IDT as gold standard, were calculated. Results On subjective evaluation, the correlation between PT and IDT was poor and sensitivity of PT was 0%. Of the seven criteria for the objective evaluation of PT, the best diagnostic performance was attained when allergen‐induced wheals were considered positive if their longest diameter was ≥8.5 mm. However, even then, the correlation with IDT was moderate, and the sensitivity of PT, albeit based on few positive IDT reactions, was low. Conclusion and Clinical Relevance At least as performed herein, PT has a poor‐to‐moderate correlation with IDT, mainly as a consequence of the lack of positive PT reactions. Further studies are needed to improve PT technique, yet, meanwhile, it cannot be recommended as a substitute for IDT. Résumé Contexte Il n'existe aucune étude portant sur la corrélation entre le prick test (PT) et le test intradermique (IDT) avec les allergènes environnementaux chez les chiens atteints de dermatite atopique (DA). Objectifs Étudier la corrélation entre PT et IDT pour deux allergènes environnementaux et calculer la sensibilité, la spécificité et l'indice de Youden du PT, en utilisant l'IDT comme étalon. Matériels et méthodes Vingt‐deux chiens atteints de DA ont été sélectionnés. Le PT a été réalisé avec des extraits d'allergènes glycérinés, ainsi que des contrôles négatifs et positifs, en utilisant le Greer Prick System. Les réactions ont été interprétées (positives/négatives) subjectivement et en utilisant sept critères objectifs, par un examinateur ignorant les résultats de l'IDT. Les réactions IDT a