Mia’s recurrent ear problem

Young domestic shorthaired cat Mia was causing her owner considerable consternation with a persistent ear problem. She had previously had a total left ear canal ablation (TECA), following a severe case of otitis externa.

When her local vet at Vets4Pets in Kettering saw that the right ear was showing marked signs of otitis externa, with crusting on the pinnal edges and bilateral aural discharge, she referred her for a multi-disciplinary consultation at Davies Veterinary Specialists, with Small Animal Surgery Specialist Ronan Doyle and Dermatology Specialist Dr Andrea Volk.

Mia had been beset with a complexity of ear problems throughout most of her young life. Having previously had severe otitis externa in her left ear, requiring a total left ear canal ablation, the right ear then began to show similar signs of otitis.

Small Animal Surgery Specialist Ronan Doyle performed a CT scan which confirmed otitis media as well as otitis externa on the right. Mia’s local lymph nodes were enlarged and otoscopic examination revealed right ear canal narrowing and marked proliferative tissue on the remainder of the left ear canal and the pinna.

A biopsy of the lining of the right ear canal revealed marked proliferative epidermal changes (acanthosis with papillary projections) with large numbers of eosinophils, also in the dermis, mixed with some mast cells and neutrophils. Bacterial culture showed E-coli and Streptococci (beta-haemolytic).

During discussion of the case between Soft Tissue and Dermatology, differential diagnoses of proliferative necrotising otitis externa and Herpes-virus-related dermatitis / otitis arose. After clinical examination by Dermatology Specialist Dr Andrea Volk, lichenifications on both Mia’s pinnae, with crusting and ulcerations as well as purulent discharge were noted. Thus, the histopathologist was asked to review the slides for possible signs for these differential diagnoses.

Dr Volk also noticed that Mia had red, thickened skin between the digits of her hind paws and around her anus and had a history of cat flu, with recurrent corneal ulcers, whereby one of the flares were at the same time as pinnal lesions had started.

Mia was prescribed a course of antibiotics to tackle the infection as well as glucocorticoids, a strong anti-inflammatory for pain management and antimicrobial ear drops, but the reason for the bilateral severe otitis externa remained puzzling. The suspicion of a Herpes virus related skin and ear disorder grew stronger.

So to re-cap, the initial examination had confirmed otitis media as well as otitis externa on the right but there was some puzzlement over the presentation of the condition. There was a suspicion that it may be proliferative and necrotising otitis and/or, because of pinnal as well as further lesions on the haired skin (between her digits on the hind paws and around her anus), a Herpes-virus-related skin/ear disorder. After a follow-up discussion between Dermatology and Pathology, a submitted PCR for Herpes virus showed positive results at a moderate level.

Whilst further investigations were still pending, Mia was prescribed a course of antibiotics (doxycycline) to tackle the infection as well as glucocorticoids, (an anti-inflammatory) to help manage her pain. As external ear disease very rarely responds to systemic antibiotics, antimicrobial ear drops were also very important, although due to Mia’s pain it was only possible to use them two weeks after the other treatments had kicked in.

At her follow up appointment three weeks later Davies’ Small Animal Surgery Specialist Ronan Doyle and Davies Dermatology Specialist Dr Andrea Volk were pleased to see that Mia was much improved. The aural discharge was nearly resolved and the skin damage had healed.

They decided to continue with the current treatment plan and delay the use of antivirals (famciclovir) for the moment. The clinical signs of right-sided middle ear disease (pain and Horner syndrome) will be monitored, and should those recur, surgical management may have to be explored, most likely ventral bulla osteotomy.

The conclusive diagnosis was Herpes-virus-related otitis and dermatitis with secondary bacterial infection.

Andrea Volk commented:

“Ronan and I were lucky to be able to work on this complicated case from a multi-disciplinary perspective to reach a diagnosis and establish a treatment plan. We hope medical management will provide Mia with a good, long term quality of life and that she won’t need a ventral bulla osteotomy to resolve the right sided otitis media. We are currently tapering her glucocorticoid dose and the patient is doing very well, and so is the owner,”