Extra‐auricular lesions of proliferative and necrotizing otitis externa in three kittens

Abstract

Background -Proliferative and necrotising otitis externa (PNOE) is a rare disorder in cats with poorly understood pathogenesis. Extra-auricular (EA) lesions recently have been mentioned in a textbook and in one case report.Objectives -To describe EA lesions associated with PNOE in three kittens.Animals -A 6-month-old female domestic short hair (DSH) cat (Case 1), an 8-month-old female DSH cat (Case 2) and a 5-month-old female DSH cat (Case 3).Methods and results -All cases exhibited classical lesions of PNOE associated with EA lesions, generalised (cases 1 and 3) or limited to eyelids (Case 2). Lesions were characterised by thick, adherent, hyperkeratotic papules coalescing to plaques and attempts to remove the hyperkeratotic plaques resulted in erosions. Histopathological examinations revealed classical features of PNOE: severe acanthosis associated with a marked lymphocytic exocytosis, satellitosis and apoptotic keratinocytes at all levels of the epidermis and the outer root sheath of hair follicles. Cases 2 and 3 resolved spontaneously. Case 1 remained stable with topical tacrolimus and oral prednisolone after a short course of ciclosporin.Conclusions and clinical importance -This report describes EA lesions of PNOE in three kittens. Such lesions may be underdiagnosed, and this report emphasises the role of a thorough clinical inspection in PNOE cases.

Proliferative necrotizing otitis externa in two young cats

“…Treatment that aids the resolution of the clinical condition is beneficial, especially as secondary bacterial infection can occur. (Mauldin, 2007;Momota, 2017;Noli, 2020;Panzuti, 2021).…”

“…Proliferative necrotizing otitis externa (PNOE) is a rare condition in young cats and was first described in 1998 as a disease affecting kittens between two and six months of age (Power, 1998). Since then, PNOE has been scarcely reported in the literature (Gross, 2005;Mauldin, 2007;Stevens and Lindner, 2012;Noli et al, 2020;Panzuti, 2021). It has been demonstrated to affect cats from two months to fourteen years of age, and mostly occurring at the age of four (Muller-Kirk, 2013;Momota et al, 2017).…”

“…Necrosis and secondary infection can cause a striking odor, and occasionally, purulent discharge is seen. In two similar reports, extra-auricular lesions of the eyelids, the face, the abdomen, axilla and groin were described (MacAuliffe, 2020;Panzuti, 2021). Up till now, the pathogenesis is not well understood.…”

“…Lesions exhibit T-cell-mediated keratinocyte apoptosis (Vidémont et al, 2010). In cases without spontaneous regression, immunomodulating medication, such as corticosteroids, ciclosporine and tacrolimus have been used (Mauldin, 2007;Momota, 2017;Panzuti, 2021) .…”

Proliferative and necrotizing otitis externa in a kitten: Case report with literature review

“…A thick dark brown exudate covers lesional area and its removal reveals underlying ulcers and erosions. Bacterial or yeast colonization is typically seen with cytological examination (Mauldin et al, 2007;Videmont and Pin, 2010;Borio et al, 2012;Stevens and Linder, 2012;Momota et al, 2016;Momota et al, 2017;McAuliffe et al, 2020;Panzuti et al,2021). Animals are otherwise healthy.…”