Veterinary dermatology最新文献

Background: Skin disease is a common complaint in veterinary medicine. Current models often use live animals. Epidermal organoids (keratinocytoids) are 3D miniature organs created in culture from single epidermal keratinocytes. These keratinocytoids can be used as an alternative to live animal studies to investigate epidermal structures and skin diseases.

Hypothesis/objective: This study's objective was to compare ultrastructural morphological features of canine keratinocytoids to those features of normal epidermis.

Results: Skin and organoids had morphologically similar components, including tight junctions, desmosomes, lamellar bodies and keratin filaments. These structures were similar in both morphology and distribution. Keratinocytes in the organoids had larger and more distinct keratohyalin granules than epidermal keratinocytes and contained small amounts of glycogen. Keratinocytes from the skin showed no glycogen accumulation.

Conclusions and clinical relevance: Canine keratinocytoids are a useful model to study canine epidermal disease from a light microscopy and ultrastructural standpoint.

Background: Dermoscopy is a noninvasive technique used for the preliminary assessment of skin lesions including neoplasms in humans and animals. Infundibular keratinising acanthoma (IKA) is a benign hair follicle neoplasm of dogs reported to represent 3.36% of all skin tumours; however, its dermoscopic features have not been investigated.

Hypothesis/objectives: The aim of this study was to describe and characterise the dermoscopic features of IKA and follicular cysts, highlighting their differential aspects and assessing the interobserver agreement of the dermoscopic parameters.

Animals: Thirty-five lesions from 10 client-owned dogs, histologically diagnosed as IKA or follicular cysts, were included in this study.

Materials and methods: The dermoscopic images of the lesions at ×10 magnification were independently evaluated on a computer screen by two ECVD board-certified veterinary specialists and one ECVD resident.

Results: Twenty-six IKAs and nine follicular cysts were included. White structureless areas were frequently observed in IKAs (92%) and in follicular cysts (66%). Surface keratin (76%), blood spots (38%) and four-dot clods (7%) were exclusively observed in IKAs, while white lines were detected in 11% of IKAs and 22% of cysts. Blood vessels were observed in 15 of the 26 IKAs and in one of the nine cysts only. Near-perfect interobserver agreement for surface keratin (κ = 0.84) and good agreement for white lines (κ = 0.78), four-dot clods (κ = 0.65), linear irregular vessels (κ = 0.66) and blood spots (κ = 0.64) was found.

Conclusions and clinical relevance: Dermoscopy represents a useful technique to assess IKA and follicular cysts in dogs.

Background: Erythemato-ceruminous otitis externa (ECOE) is commonly associated with Malassezia spp. and microbial imbalance.

Hypothesis/objective: To assess the clinical performance of an ear cleaner in dogs suffering from ECOE associated with Malassezia spp. overgrowth and to measure its impact on the microbiota.

Animals: Thirty privately owned dogs suffering from mild-to-moderate ECOE associated with Malassezia spp. overgrowth.

Materials and methods: Pruritus score (PS), clinical score (0-3 Otitis Index Score [OTIS3]: based on secretions, erythema, hyperplasia and ulceration) and cytological score (CS) were assessed on Day (D)0, D7, and D14. Sterile ear swabs were used on D0 and D14 to perform fungal culture DNA extraction, and PCR amplification of the 18 ITS and 16S rRNA gene was carried out to evaluate the composition and changes of the otic microbiome. Ears were cleaned with a cerumenolytic ear cleanser daily, every other day, or twice a week depending on the secretion score.

Results: Fifty-seven ears (30 dogs) completed the study. PS, OTIS-3, and CS were significantly decreased at D7 and D14 (-45%, -43%, -60% and -77%, -66%, -76%, respectively; p < 0.0001 Wilcoxon test). Fungal culture was positive (Malassezia spp.) in only 34 ears at D0 and was negative in all ears at D14. Mycobiota composition was significantly different before and after treatment with an increase of fungal diversity (Shannon index; p < 0.003 Wilcoxon test) at D14 compared to D0. There was no change in bacterial composition.

Conclusions and clinical relevance: In case of ECOE associated with Malassezia spp. overgrowth, the use of the tested ear cleaner showed a positive impact on the fungal dysbiosis and Malassezia spp. overgrowth.

Background: The effects of oral daily probiotic/postbiotic supplementation (ODPPS) on the skin microbiota of dogs have not been investigated previously.

Objectives: This prospective analytical cohort study describes the effect of ODPPS on the canine skin microbiota after 30-90 days of supplementation using culture-based and full-length 16S rRNA gene sequence analysis.

Animals: Twelve client-owned golden retrievers free of dermatological disease, living in the same environment.

Materials and methods: Skin (axillae and inguinal) swab samples were collected on Day (D)0. All dogs commenced ODPPS, and skin swab samples were taken from the same sites on D30 and D90. Swabs were cultured on sheep blood agar at 37°C for 24 h and bacterial colonies identified. DNA was extracted to obtain full-length 16S ribosomal RNA gene for microbiota profiling.

Results: Culture-dependent methods demonstrated reduced Staphylococcus pseudintermedius prevalence in inguinal tissue following ODPPS (p = 0.05). In the axillae, microbiota compositional differences were demonstrated at D90 compared to D0. A notable increase in beneficial skin-associated bacteria was observed in the axillae at D90 compared to D0, including Dubosiella newyorkensis (false discovery rate [FDR] p = 0.02) and Lactobacillus acidophilus (FDR p = 0.02). Higher bacterial genera diversity was observed on D90 of ODPPS.

Conclusions and clinical relevance: This study provides a comprehensive analysis of the canine skin microbiota using advanced long-read sequencing. The findings suggest that ODPPS could be a promising strategy for improving skin health by modulating the microbiota and reducing the risk of skin infections.

Background: Dermoscopy is a noninvasive diagnostic tool that provides a magnified view of skin structures. While dermoscopy is described for certain canine dermatological diseases, large-scale studies evaluating normal skin are lacking.

Hypothesis/objective: This study aimed to correlate dermoscopic findings with histopathological results in healthy canine skin to enhance understanding of dermoscopic microanatomy and pigmentation patterns.

Animals: Healthy, adult, shelter dogs (n = 121).

Materials and methods: After general anaesthesia for prescheduled sterilisation procedures, four regions on each dog were assessed using a handheld dermoscope followed by collecting a biopsy for histopathological investigation. Dermoscopic assessment included skin colour and pattern, presence of scale and blood vessel number. Dermoscopic findings were correlated with histopathological characteristics.

Results: Dermoscopy identified grey as the most common skin colour, diffuse as the primary pattern, most commonly mild scale and primarily absent blood vessels. Dermoscopy correlation with histopathological results identified moderate scale as more likely to have hyperkeratosis, and no significant correlation between visualised blood vessels and number of endothelial cells. Furthermore, the dermoscopic colour brown was more likely to have melanin within each epidermal layer, while white was less likely to have melanin within each layer. Despite the lack of gross and dermoscopic inflammation, such as erythema, 53 of 484 sites had histopathological evidence of inflammation, with primarily mild mastocytic and eosinophilic superficial dermatitis.

Conclusions and clinical relevance: Dermoscopy can identify characteristics in canine skin that correlate with histopathological results, yet mild inflammation may remain undetected. This correlation better establishes baselines for future studies utilising dermoscopy when assessing dermatological diseases.

Background: Canine pyoderma is one of the most common presentations in small animal practice, frequently leading to antimicrobial prescribing.

Objectives: To provide clinicians with antimicrobial treatment guidelines for staphylococcal pyoderma, including those involving meticillin-resistant staphylococci. Guidance on diagnosing surface, superficial and deep pyoderma, and their underlying primary causes is included. Recommendations aim to optimise treatment outcomes while promoting responsible antimicrobial use.

Materials and methods: Evidence was gathered from a systematic literature review of English-language treatment studies for canine pyoderma up to 23/12/2023. Quality was assessed using SORT criteria and combined with authors' consensus evaluation. Recommendations were voted on in an iterative process, followed by a Delphi-style feedback process before final agreement by the authors.

Results: Cytology should be performed in all cases before antimicrobials are used. Topical antimicrobial therapy alone is the treatment-of-choice for surface and superficial pyodermas. Systemic antimicrobials should be reserved for deep pyoderma and for superficial pyoderma when topical therapy is not effective. Systemic therapy, with adjunctive topical treatment, is initially provided for 2 weeks in superficial and 3 weeks in deep pyoderma, followed by re-examination to assess progress and manage primary causes. First-choice drugs have expected efficacy against the majority of meticillin-susceptible Staphylococcus pseudintermedius; for all others, laboratory testing should confirm susceptibility and exclude suitability of safer alternatives. As culture and susceptibility testing are essential for rationalising systemic therapy, laboratories and practices should price them reasonably to encourage use. Proactive topical therapy using antiseptics may help prevent recurrences.

Conclusions and clinical relevance: The accessibility of the skin offers excellent, achievable opportunities for antimicrobial stewardship.

Background: Besides pruritus and skin lesions, cats with feline atopic skin syndrome (FASS) may have seborrhoea.

Hypothesis/objectives: The aim of this pilot study was to investigate whether an adsorbent mousse containing tapioca starch, adelmidrol and a nonpharmacological antimicrobial complex could decrease FASS-associated seborrhoea in cats.

Animals: Seven client-owned cats with FASS were included based on the presence of seborrhoea and pruritus (>4 cm on the validated feline pruritus Visual Analog Scale [VAScat]), regardless of the concomitant administration of antiallergic drugs, provided that they were used for ≥1 month before study entry and maintained unchanged.

Materials and methods: Cats were evaluated weekly by owners and every other week by veterinary surgeons for 2 (optionally 4) weeks using a four-item skin seborrhoeic index (SSI). The VAScat and the scoring feline allergic dermatitis (SCORFAD) index also were used to assess pruritus and skin lesion severity, respectively. The Wilcoxon signed-rank test was used for pre- versus post-treatment comparisons.

Results: At the end of Week 2, the mean score value for SSI was significantly decreased (p = 0.016). At the same time point, the mean severity of pruritus and the mean SCORFAD index value had also decreased (p = 0.016). Moreover, 86% of the investigators were 'satisfied' or 'very satisfied' with the tested mousse. Four cats continued the study up to Week 4 and showed a further, albeit nonsignificant, decrease in all evaluated scores.

Conclusions and clinical relevance: These preliminary findings have promising implications for clinical practice in cats with FASS-associated seborrhoea and are worth further investigation.

Background: Canine cutaneous epitheliotropic lymphoma (CEL) is a rare neoplastic disease with poor prognosis. Oclacitinib, a Janus kinase inhibitor primarily used to treat allergic and atopic dermatitis in dogs, may also cause other skin diseases.

Objectives: This study aimed to evaluate the efficacy of oclacitinib in the treatment of canine cutaneous lymphoma.

Animals: Eight client-owned dogs with CEL were included in the study.

Materials and methods: The dogs were administered oclacitinib. This study examined the immunological characteristics, time to treatment initiation, dosage, cutaneous lesions and pruritus, adverse events, survival time and prior oclacitinib use.

Results: Only one of the eight dogs (12.5%) showed symptomatic improvement after oclacitinib treatment, with no clinical improvement observed in the other cases. Improvement in pruritus was noted in only one dog. Adverse events included mild leucopenia in one dog, which did not significantly affect prognosis. The median survival time after diagnosis was 228.5 days.

Conclusions and clinical relevance: These results suggest that oral oclacitinib has limited efficacy in the treatment of canine CEL. Larger prospective studies are recommended to further investigate the optimal dose, treatment duration and potential combination therapies involving oclacitinib.