Does mometasone ear medicine affect allergy skin tests in dogs

Abstract

BACKGROUND: Topical ear medications, often containing a glucocorticoid, are used to treat the clinical signs of atopic otitis in dogs. Studies have looked at the inhibitory effect of topical glucocorticoids on intradermal testing (IDT), but only one previously published study evaluated the influence of an otic glucocorticoid on the results of IDT in dogs. HYPOTHESIS/OBJECTIVES: To assess what influence the absorption of the diester glucocorticoid mometasone furoate (MF) had on intradermal test immediate reactions, to determine an appropriate withdrawal time prior to IDT. METHODS: Twenty atopic dogs were enrolled. On day 0, histamine, rabbit anticanine IgE antiserum and saline were injected intradermally. After 20 min, a global wheal score (GWS) was determined. The otic medication, MF, was applied once daily for 14 days. Intradermal injections were then repeated and, if the GWS was within 25% of pretreatment values, the study was completed for this dog. If the GWS had decreased by ≥25% from the baseline value, the otic medication was withdrawn, and the GWS was repeated every 7 days until its value was within 25% of the original GWS. RESULTS: Three of the 20 dogs completed the study on day 14, while 17 of 20 dogs ended it on day 21, 7 days after withdrawal of the drug, MF. CONCLUSIONS AND CLINICAL IMPORTANCE: Results from this study show that a withdrawal period of ≤7 days is possible before performing IDT in atopic dogs with active otitis externa treated with ≤14 days of MF.