Do you have a puzzling dermatological case? Is it not responding the way you expect? I’d suggest a skin biopsy…
I recently came across a puzzling case in a nine-year-old cocker spaniel called Olli, which presented with a persistent Pseudomonas otitis. This resolved with appropriate antibiotic therapy based on sensitivity results, but erythema and ulceration of the medial aspect of the pinna remained. The otitis then relapsed.
No response to the food trial was evident and thyroid function was normal, so I suggested a skin biopsy, imagining the results would confirm my suspicion of idiopathic seborrhoea of the cocker spaniel.
To my surprise, however, this was not the case.
Histopathology reported interface dermatitis with apoptosis, suggesting it as immune-mediated or possibly drug associated. We are now starting Olli on some immunosuppressive therapy.