What recent advances have changed the approach to treating recurrent otitis externa in dogs?

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The most impactful recent advance is the formal adoption of a two-phase induction-then-maintenance protocol, replacing the historical pattern of treating each flare in isolation. The induction (stabilization) phase uses topical antimicrobial-antifungal-glucocorticoid combinations to achieve remission, followed by a proactive maintenance phase with topical hydrocortisone aceponate (HCA) to prevent relapse — a framework now supported by clinical outcome data.12 In one protocol, the stabilization phase used a ciprofloxacin-clotrimazole-betamethasone suspension, followed by topical HCA for 90 days in the proactive phase; most dogs showed no recurrence of otitis throughout the remaining observation period, with marked reduction in both cytological and clinical scores.2 The primary-secondary-predisposing-perpetuating (PSPP) framework has been reaffirmed as non-negotiable: all recurrent otitis in dogs is secondary, and treating the infection without diagnosing the primary cause guarantees relapse. Allergic dermatitis — most commonly atopic dermatitis — is the most frequent primary cause of chronic and recurrent otitis externa.11113 More than 50% of dogs with atopic dermatitis exhibit otitis externa.7 Food allergy is also a recognized primary cause, while flea allergy dermatitis is not associated with allergic otitis externa.13 Other primary causes to rule out include parasites, foreign body, neoplasia, endocrinopathy, and keratinization disorders.13 Early dermatology collaboration produces substantially better outcomes than primary care management alone. The median time to otitis recurrence under collaborative board-certified veterinary dermatologist (BCVD) care is 171 days, compared to 21 days under primary care veterinarian management alone.4 The median number of recurrences drops from 4 under primary care to 2 with BCVD collaboration.4 Proliferative ear canal changes improve in 91% of cases under BCVD care versus 13% under primary care management.4 Referral or consultat