Retrospective review of diphenhydramine versus diphenhydramine plus glucocorticoid for treatment of uncomplicated allergic reaction in dogs.

OBJECTIVE: To report the outcome of treatment of uncomplicated allergic reactions in dogs with diphenhydramine vs diphenhydramine plus glucocorticoid and to determine the incidence rate of uncomplicated allergic reactions DESIGN: Retrospective study between January 1, 2012 and August 15, 2018. SETTING: Privately owned, 24-hour emergency and specialty referral veterinary hospital. ANIMALS: Eight hundred and eighty cases of dogs treated for uncomplicated allergic reaction with diphenhydramine alone or in combination with a glucocorticoid. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Two hundred ninety-nine dogs were treated with diphenhydramine alone, and 581 were treated with diphenhydramine plus Dex SP. There was no difference between the 2 groups for response to initial therapy, need for additional veterinary intervention after discharge, or persistent signs at follow-up. The cumulative incidence of emergency department presentation for uncomplicated allergic reaction in this hospital was 1.2%. CONCLUSIONS: There was no difference in measured outcomes between dogs treated with diphenhydramine alone vs those treated with a glucocorticoid in addition to diphenhydramine in this population of dogs.