The influence of mometasone furoate ear solution on intradermal test immediate reactions in dogs with atopic dermatitis

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 If the GWS had decreased by ≥25% from the baseline value, the otic medication was withdrawn, and the GWS was repeated every 7 days until its value was within 25% of the original GWS .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 .