Cutaneous apocrine gland neoplasia in 16 captive African wild dogs (Lycaon pictus).

This retrospective study documents the occurrence of single and multiple cutaneous apocrine gland tumours (CATs) on the dorsal midline of 16 captive African wild dogs (AWDs, Lycaon pictus) derived from 161 submissions to diagnostic laboratories in South Africa, France and Germany between 1997 and 2022. Animals included in the study came from zoological institutions in South Africa (n = 2), France (n = 5) and Germany (n = 1) and ranged from 5 to 14 years of age. Fifteen affected animals were female (94%) and one was male. CATs presented as raised, hairless, multilobular, grey firm masses, consistently located along the dorsal midline. Apart from a single cutaneous apocrine adenoma and a cystadenoma occurring concurrently with two non-cystic adenocarcinomas, neoplasms were consistent with malignant cutaneous apocrine adenocarcinomas with lymphatic spread and visceral metastases. Advanced age and female sex were identified as risk factors. A genetic component or association with the increasing use of GnRH agonist contraceptives was suspected but could not be established. This study highlights the need for close clinical monitoring of AWDs over the age of 5 years for the development of CATs along the dorsal midline and supports early surgical intervention. More research is needed to determine the role of inbreeding, endocrine changes and husbandry factors that may play a role in the development of CATs on the dorsal midline of AWDs.

Macroscopic Skin Examination Can Determine the Number of Strips Necessary to Study the stratum corneum in Dogs.

To evaluate the skin barrier, the stratum corneum (SC) must be isolated and extracted. Currently, skin biopsy is the gold standard method to investigate skin immunology and the presence of biomarkers in dogs. However, a standardized, non-invasive tool to exclusively remove the SC would be of great interest to study healthy and atopic dogs. In this study, we performed D-squames® tape stripping with standardized pressure on seven healthy beagle dogs. A control site was defined and then 25 strips, 50 strips and as many strips as needed to achieve a shiny appearance of the skin were performed on three different experimental sites. After stripping, blinded histopathological examination of a skin biopsy from each site was performed. The number of tape strips required for the skin to become shiny varied between individuals, with a mean of 40 (29-50) strips. There was no significant difference in SC depth between the control site and the site that underwent 25 tape strips. In contrast, the use of 50 strips removed almost all of the SC, with a mean remaining SC depth of 7.82 µm. These data suggest that this non-invasive method can effectively remove the SC, with individual variability, and that a shiny appearance of the skin after stripping can be used as an accurate marker of SC removal.

Skin Barrier Reinforcement Effect Assessment of a Spot-on Based on Natural Ingredients in a Dog Model of Tape Stripping.

Skin barrier restoration is an important part of atopic dermatitis therapy. We investigated the effect of a spot-on containing plant-based essential fatty acids and essential oils on skin barrier parameters in a dog model of acute skin barrier disruption, using five healthy beagle dogs maintained in a laboratory setting. Four test sites on the dorsum and a control site on the abdomen were defined on each dog. Transepidermal water loss (TEWL) and skin surface hydration (SSH) were measured before and after tape stripping on the first day and then for three consecutive days, over four consecutive weeks. The spot-on was applied at the end of each of the first three weeks. The increase in TEWL after tape stripping was reduced after the spot-on application and reached control values in Weeks 3 and 4. SSH after tape stripping was reduced in Week 4 compared with the baseline. Thus, the ATOP 7® spot-on significantly reduced acute skin barrier impairment in a dog model. The use of this product should be further evaluated as a potential treatment for skin barrier defects such as canine atopic dermatitis.

Effect of an ear cleaner instillation containing lipacids in a model of re-acidification of the external auditory canal in dogs.

BACKGROUND: In humans, the acidic pH of the ear canal plays a protective role against infection and a change towards alkalinity of the external auditory canal (EAC) is a local factor in the progression of acute to chronic otitis externa (OE). The use of acidic preparations alone for treatment of OE without concurrent antibiotic use is well-documented in humans. In dogs, only one study has investigated the EAC pH in healthy dogs and in dogs with OE, and investigations to understand the role of EAC pH in the pathogenesis of canine OE are lacking. HYPOTHESIS/OBJECTIVES: To obtain physiological EAC pH values in beagle dogs. To develop a model of re-acidification of the EAC in dogs and to investigate how an acidic solution may accelerate the return to a physiological pH. ANIMALS: Ten healthy beagle dogs in a laboratory setting. MATERIALS AND METHODS: A model of re-acidification of the EAC was developed by instillation of a pH 10.1 phosphate-buffered saline (PBS) solution and the subsequent acidic effect of an ear cleaner containing lipacids was evaluated in this model. RESULTS: Mean physiological EAC pH was 6.12 (± 0.36). EAC re-acidification took up to 9 h in this model. Mean pH values dropped immediately to 6.38 (± 0.27) on ears treated with an acidic ear cleaner. No abrupt drop was observed of the mean pH values for the control ears. CONCLUSION AND CLINICAL IMPORTANCE: This study confirms that physiological EAC pH in dogs is acidic. This model of re-acidification of the EAC pH allows investigations on acidic properties of topical ear products in healthy ears.

Contexte - Chez l'homme, le pH acide du conduit auditif joue un rôle protecteur contre l'infection et l'évolution vers l'alcalinité du conduit auditif externe (CAE) et est un facteur local de progression de l'otite externe (OE) aiguë à chronique. L'utilisation de préparations acides seules pour le traitement de l'OE sans utilisation concomitante d'antibiotiques est bien documentée chez l'homme. Chez les chiens, une seule étude a étudié le pH du CAE chez les chiens en bonne santé et chez les chiens atteints d'OE, et les recherches pour comprendre le rôle du pH du CAE dans la pathogenèse de l'OE canine font défaut. Hypothèses/objectifs - Obtenir des valeurs physiologiques de pH du CAE chez des chiens beagle. Développer un modèle de réacidification du CAE chez le chien et étudier comment une solution acide peut accélérer le retour à un pH physiologique. Animaux - Dix chiens beagle de laboratoire en bonne santé. Matériels et méthodes - Un modèle de réacidification du CAE a été développé par instillation d'une solution saline tamponnée (PBS) à pH 10,1 et l'effet acide ultérieur d'un nettoyant pour oreilles contenant des lipacides a été évalué dans ce modèle. Résultats - Le pH physiologique moyen du CAE était de 6,12 (± 0,36). La réacidification du CAE a pris jusqu'à 9 h dans ce modèle. Les valeurs moyennes du pH chutent immédiatement à 6,38 (± 0,27) sur les oreilles traitées avec un nettoyant auriculaire acide. Aucune chute brutale n'a été observée des valeurs moyennes de pH pour les oreilles témoins. Conclusion et importance clinique - Cette étude confirme que le pH physiologique du CAE chez le chien est acide. Ce modèle de réacidification du pH du CAE permet des investigations sur les propriétés acides des produits topiques auriculaires dans des oreilles saines.

Introducción; en humanos, el pH ácido del canal auditivo juega un papel protector contra la infección y un cambio hacia la alcalinidad del canal auditivo externo (EAC) es un factor local en la progresión de la otitis externa (OE) aguda a crónica. El uso de preparaciones ácidas solas para el tratamiento de la OE sin el uso concomitante de antibióticos está bien documentado en humanos. En perros, solo un estudio ha investigado el pH de EAC en perros sanos y en perros con OE, y faltan investigaciones para comprender el papel del pH de EAC en la patogenia de la OE canina. Hipótesis/objetivos - Obtener valores de pH fisiológico de EAC en perros beagle. Desarrollar un modelo de reacidificación del EAC en perros e investigar cómo una solución ácida puede acelerar el retorno a un pH fisiológico. Animales- diez perros beagle sanos en un laboratorio. Materiales y métodos- se desarrolló un modelo de reacidificación del EAC mediante la instilación de una solución salina tamponada con fosfato (PBS) de pH 10,1 y se evaluó en este modelo el efecto ácido subsiguiente de un limpiador de oídos que contenía lípidos. Resultados - El pH fisiológico medio del EAC fue de 6,12 (± 0,36). La reacidificación de EAC tomó hasta 9 h en este modelo. Los valores medios de pH cayeron inmediatamente a 6,38 (± 0,27) en los oídos tratados con un limpiador de oídos ácido. No se observó una caída abrupta de los valores medios de pH para los oíds de control. Conclusión e importancia clínica- este estudio confirma que el pH fisiológico de EAC en perros es ácido. Este modelo de reacidificación del pH de EAC permite realizar investigaciones sobre las propiedades ácidas de los productos tópicos para el oído en oídos sanos.

Contexto - Em humanos, o pH ácido do conduto auditivo exerce uma grande função protetora contra infecções e a alcalinização do conduto auditivo externo (CAE) é um fator local de progressão de otite externa (OE) aguda para crônica. A utilização unicamente de formulações ácidas para o tratamento de OE sem a utilização concomitante de antibióticos é bem documentada em humanos. Em cães, apenas um estudo investigou o pH do CAE em cães saudáveis com OE, e são escassas as pesquisas investigando o papel do pH do CAE na patogênese da OE. Hipótese/objetivos - Se obter os valores fisiológicos do pH dos CAEs de cães Beagle. Desenvolver um modelo de re-acidificação do CAE em cães e investigar como uma solução ácida pode acelerar o retorno ao pH fisiológico original. Animais - Dez cães Beagle saudáveis de laboratório. Materiais e Métodos - Um modelo de re-acidificação do CAE foi desenvolvido por instilação de solução salina tamponada com fosfato (PBS) com um pH 10,1 e o efeito acidificante subsequente de um limpador de ouvido contendo ácidos lipídicos foi avaliado neste modelo. Resultados - O pH fisiológico médio do CAE foi de 6,12 (± 0,36). A re-acidificação do CAE levou até 9h neste modelo. Os valores médios de pH caíram imediatamente para 6,38 (± 0,27) nas orelhas tratadas com um limpador otológico ácido. Não foi observada queda abrupta dos valores médios de pH para as orelhas controle. Conclusão e importância clínica - Este estudo confirmou que o pH fisiológico do CAE de cães é ácido. Este modelo de re-acidificação do pH do CAE permite investigações sobre as propriedades acidificantes de produtos otológicos tópicos para orelhas saudáveis.

Clinical Guidelines for the Use of Antipruritic Drugs in the Control of the Most Frequent Pruritic Skin Diseases in Dogs.

Pruritus is a common clinical sign in many skin disorders and is currently the main complaint in canine dermatology. Pruritic skin diseases can affect the quality of life of dogs and their owners. Several families of antipruritic drugs are available to help control pruritus in dogs. The aim of this review is to help practitioners select the most appropriate symptomatic treatment in the most frequent situations of dermatological pruritus in dogs. The molecules reviewed here are systemic and topical glucocorticoids, antihistamines, ciclosporin, oclacitinib and lokivetmab. A level of evidence (1, 2 or 3) has been established according to a detailed algorithm for each individual study in the literature published between 1990 and March 2021. The guidelines result from evidence grading using the strength of recommendation taxonomy (SoRT) and clinical recommendations using a thorough methodology.

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

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.

Long-term successful treatment of a donkey with cutaneous lupus erythematous with methotrexate.

Cutaneous lupus erythematosus (CLE) is a rare immune-mediated dermatitis. To the best of the authors' knowledge it has not been described in donkeys. A 5-year-old male neutered donkey, living in south-east France, was diagnosed with CLE. Clinical signs included generalized symmetrical areas of alopecia, erythema, crusting and scales. Diagnostic tests included examination of skin biopsy samples by histopathological and immunohistochemical analysis which demonstrated an interface dermatitis with CD8+ T cells. The skin condition was successfully treated initially with glucocorticoids and methotrexate; successful long-term maintenance was associated with administration of methotrexate.

Le lupus cutané érythémateux (CLE) est une dermatite à médiation immune rare. A la connaissance des auteurs, il n'a pas été décrit chez le singe. Un singe mâle castré de 5 ans, vivant dans le sud-est de la France a été diagnostiqué avec CLE. Les signes cliniques incluaient des zones symétriques généralisées d'alopécie, d'érythème, de croûtes et de pellicules. Les tests diagnostics comprenaient un examen histopathologique et immunohistochimique de biopsies cutanées qui ont révélé une dermatite d'interface avec cellules T CD8+. La dermatose a été traitée avec succès initialement avec des corticoïdes et du méthotrexate; un traitement efficace au long cours a été associé avec l'administration de méthotrexate.

El lupus eritematoso cutáneo (CLE) es una rara dermatitis inmunomediada. A entender de los autores, esta enfermedad no se ha descrito en burros. Un burro castrado macho de 5 años de edad, que vive en el sureste de Francia fue diagnosticado con CLE. Los signos clínicos incluyeron áreas simétricas generalizadas de alopecia, eritema, costras y escamas. Las pruebas de diagnóstico incluyeron el examen de muestras de biopsia de piel mediante análisis histopatológico e inmunohistoquímico que demostró una dermatitis de interfase con células T CD8+. La condición de la piel se trató con éxito inicialmente con glucocorticoides y metotrexato; el control exitoso a largo plazo de la enfermedad se obtuvo con la administración de metotrexato.

O lúpus eritematoso cutâneo (LEC) é uma dermatite imunomediada rara. De acordo com os conhecimentos do autor, a doença ainda não foi descrita em jumentos. Um jumento macho castrado de cinco anos de idade, habitante do sul da França, foi diagnosticado com LEC. Os sinais clínicos incluíram alopecia, eritema, crostas e descamação generalizadas e simétricas. Os testes diagnósticos utilizados foram avaliação de amostras de biópsia por análise histopatológica e imunohistoquímica, que demonstraram dermatite de interface com células T CD8+. A dermatopatia foi tratada satisfatoriamente inicialmente com glicocorticoide e metotrexato; a manutenção satisfatória a longo prazo foi associada à administração de metotrexato.

Equine pastern vasculitis in a horse associated with a multidrug-resistant Pseudomonas aeruginosa isolate.

BACKGROUND: Equine pastern vasculitis is an uncommon disorder in horses. Underlying causes are difficult to assess, especially bacterial infections. CLINICAL SUMMARY: A 13-year-old French saddle gelding horse presented for evaluation of a six weeks history of pastern dermatitis. Histopathological examination of skin biopsy samples revealed small vessel vasculitis. A pure growth of a multidrug-resistant Pseudomonas aeruginosa (MRPA) was obtained from a deep skin biopsy. Clinical remission was observed after a six week course of enrofloxacin and lesions did not recur. CONCLUSIONS AND CLINICAL IMPORTANCE: To the best of the authors' knowledge, this is the first report of a pastern vasculitis associated with MRPA and successfully treated with a six week course of enrofloxacin.

Granulomatous mural folliculitis in a dog treated with ciclosporin and methotrexate.

BACKGROUND: Canine granulomatous mural folliculitis is a very rare cause of scarring alopecia with unknown pathogenesis. HYPOTHESIS/OBJECTIVES: To report a case of granulomatous mural folliculitis in a dog treated with ciclosporin (Cs) and methotrexate (MTX). ANIMAL: A 13-year-old spayed female Pyrenean shepherd dog with a one month history of scarring alopecia. METHODS AND RESULTS: Histopathological examination revealed a granulomatous and lymphocytic mural and necrotizing folliculitis and furunculosis. Immunochemistry, using antibodies for CD3, CD204, CD206, IBA-1 and CD208, revealed that CD3+ lymphocytes were infiltrating the outer root sheath along with IBA-1+ or CD204+ cells. Ciclosporin (5 mg/kg once daily) and MTX (0.25 mg/kg once weekly then 0.5 mg/kg once weekly) were initiated simultaneously, and Cs was stopped after stabilization of the lesions. The dog's skin disease was stable for six months. CONCLUSIONS AND CLINICAL IMPORTANCE: To the best of the authors' knowledge, this is the first report of the long-term management of a granulomatous mural folliculitis in a dog. Ciclosporin and MTX appeared to be an effective treatment option. Additional treated cases are needed to assess the effectiveness of MTX in canine immune-mediated diseases.

Efficacy of two formulations of afoxolaner (NexGard® and NexGard Spectra®) for the treatment of generalised demodicosis in dogs, in veterinary dermatology referral centers in Europe.

BACKGROUND: A multi-centre field trial was conducted to evaluate the efficacy of afoxolaner based chewables (NexGard® or NexGard Spectra®) for the treatment of generalised demodicosis caused by Demodex canis in dogs under field conditions in France, Italy and Poland. METHODS: Client-owned dogs, diagnosed positive for Demodex mites by pre-treatment skin scrapings and presenting clinical signs of generalised demodicosis were included. Dogs were orally treated with afoxolaner three times at monthly intervals. Of the 50 dogs enrolled, 48 completed the whole study. Efficacy of the treatments was assessed monthly by Demodex mite counts and physical examination with special regard to the severity and extension of skin lesions. RESULTS: Treatments were well tolerated in all dogs and resulted in a rapid reduction of mites, with all post-treatment mite counts significantly lower than baseline. The number of mites was reduced by 87.6%, 96.5% and 98.1% on Days 28, 56 and 84, respectively. In addition, the skin lesion severity and extent scores as well as the pruritus were all significantly lower at all post-treatment visits compared to the pre-treatment assessment. CONCLUSIONS: This clinical field study demonstrated that monthly administrations of afoxolaner in NexGard® or NexGard Spectra®, offered a convenient and reliable solution for the treatment of canine generalised demodicosis.

Pharmacokinetics of low-dose methotrexate in healthy beagle dogs.

Methotrexate may be an alternative to ciclosporin in the treatment of canine atopic dermatitis (cAD) as suggested by recent data. The aim of the study was to investigate both the tolerance and the pharmacokinetic behavior of methotrexate (MTX) in plasma, following intravenous (i.v.), subcutaneous (s.c.) or oral (OR) administration over several weeks. Six healthy dogs were given oral MTX once a week, respectively, per dog at 2.5 mg/1 week, 5 mg/4 weeks, 7.5 mg/3 weeks, 10 mg/6 weeks and 12.5 mg/5 weeks. No clinically relevant abnormalities of laboratory parameters were noticed. A high inter-individual variation of MTX plasma concentration was observed with a suspicion of saturation phenomenon in absorption. To compare with other routes of administration, six healthy beagle dogs followed a crossover design study at 7.5 mg per dog MTX. The absolute bioavailability was 93% for SC injection and 30% for the oral route. The inter-individual variability was quite low following SC administration compared to oral route. Just as in human, given the substantial variability of oral absorption, clinicians cannot assume consistent oral bioavailability of MTX. Therefore, they may consider switching dogs to the SC route in case of absence of clinical response with a weekly oral dose.

Skin lesions in Aubrac cows strongly associated with fly bites (Haematobia irritans).

BACKGROUND: The horn fly Haematobia irritans is known to cause problems in cattle including weight loss and decreased milk production; cutaneous lesions have not been widely reported and descriptions of the clinical manifestations are quite variable. HYPOTHESIS/OBJECTIVES: This study describes the clinical and histopathological lesions of several Aubrac cows that presented with focal to confluent areas of alopecia, skin scaling and thickening, suspected to be induced by H. irritans bites. ANIMALS: Twenty seven, three- to six-year-old Aubrac cows, kept in mountain pastures in France, that presented with an apparently asymptomatic alopecic dermatosis. METHODS: Samples for skin cytological evaluation, skin scrapings and trichograms were examined; also, skin biopsy specimens from affected animals were used for histopathological examination. RESULTS: Clinical lesions consisted of focal to coalescing, symmetrical areas of hair loss and scaling, located on the back, flanks, and lateral and caudal aspects of the thighs. Histopathological examination revealed perivascular, oedematous, eosinophilic dermatitis with eosinophilic folliculitis and furunculosis. Species identification of several flies captured on the cows revealed H. irritans. The final clinicopathological diagnosis was eosinophilic dermatitis and folliculitis and furunculosis, suspected to be due to H. irritans fly-bite. CONCLUSION AND CLINICAL IMPORTANCE: Fly-bite (H. irritans) dermatitis should be included in the differential diagnosis of alopecic dermatoses in cows.

Clinical and histopathological aspects of an alopecia syndrome in captive Andean bears (Tremarctos ornatus).

BACKGROUND: Captive Andean bears (Tremarctos ornatus) develop a distinct alopecic syndrome of unknown aetiology. HYPOTHESIS/OBJECTIVES: To describe the histological features of healthy Andean bear skin, to define the clinical and histopathological features of Andean bears with signs of alopecia, and to propose an aetiopathogenesis. ANIMALS: Eighteen healthy Andean bears housed in 12 European zoos and 13 Andean bears with mild to severe alopecia housed in nine European zoos. METHODS: Two surveys describing signalment and clinical features of affected bears; follicular density was measured in a single healthy bear using a dermatoscope; cytological samples were collected by tape stripping from two healthy and three alopecic bears; skin biopsies were collected for histological evaluation from healthy and alopecic bears; immunohistochemistry (CD3, AE1/AE3 cytokeratins) was performed when lymphocytic inflammation was observed. RESULTS: The syndrome is an acquired, slowly progressive alopecia. Bears are otherwise healthy. Histological features include a dermal inflammatory infiltrate composed of T lymphocytes and eosinophils; atrophy of hair follicles at the level of or below the isthmus, and lymphocytic infiltration of hair follicles and the epidermis. Multinucleated giant cells were present in the outer root sheaths of hair follicles in five bears. CONCLUSION AND CLINICAL IMPORTANCE: Andean bear alopecia syndrome is an acquired, progressive alopecia with histological features consistent with a lymphocytic immune-mediated reaction directed against follicular sheaths and the epidermis. Trigger factors have not been identified. Further studies are indicated to define the features of this multifactorial syndrome.

Successful medical treatment of an Aspergillus terreus mycetoma of the nostril/lip in a 16-year-old Fjord pony gelding with pituitary pars intermedia dysfunction.

BACKGROUND: Mycetoma is a chronic, proliferative lesion of cutaneous/subcutaneous tissue characterized by draining tracts and granules in the discharge caused by actinomycetes (actinomycetoma) or filamentous fungi (eumycotic mycetoma). OBJECTIVES: This case report describes the unusual finding of a cutaneous mycetoma of the lateral wing of the right nostril in a gelding. ANIMAL: A 16-year-old Fjord gelding with suspected pituitary pars intermedia dysfunction (PPID) was presented for evaluation of a nonpainful, firm and raised mass involving the lateral wing of the right nostril and the lip. METHODS AND RESULTS: Cytological examination of the mass showed marked pyogranulomatous inflammation and histopathological examination revealed a fungal mycetoma. Fungal culture identified the causative organism as Aspergillus terreus, which is not known for its propensity to cause either dermal granulomas or mycetoma in domestic animals. Further investigation, including a TRH stimulation test, led to a diagnosis of PPID (Cushing's disease), which may have led to immunosuppression of the animal and increased susceptibility to infection. CONCLUSIONS AND CLINICAL IMPORTANCE: The horse was treated medically with pergolide for the PPID and oral potassium iodide for the fungal infection, with good therapeutic response and no relapse after five months. Surgical debridement or excision was not performed. To the best of the authors' knowledge, this is the first case report of a cutaneous mycetoma caused by A. terreus in a horse.