Veterinary dermatology最新文献

Background: The types of skin lesions in canine epitheliotropic cutaneous T-cell lymphoma (ECTCL) vary markedly; however, the mechanisms underlying this diversity remain unclear. Human ECTCL exhibits clonal heterogeneity, with different clones of neoplastic lymphocytes being observed in skin lesions from the same patients. Therefore, we hypothesised that diversity in skin lesions may be attributed to clonal heterogeneity.

Objectives: To evaluate clonality and its association with skin lesions.

Materials and methods: PCR for T-cell receptors was performed on 25 formalin-fixed paraffin-embedded lesional skin samples derived from eight ECTCL cases. A fragment analysis was performed to establish whether clonal patterns were identical or nonidentical between lesions. The associations of clonal patterns with the types and histopathological features of skin lesions were investigated by statistical analyses. A transcription analysis was also conducted to examine the expression of recombination-activating gene (RAG)1 in skin lesions.

Results: The fragment analysis identified only one case with an identical clonal pattern in all skin lesions. Nonidentical clonal patterns were detected in the seven other cases. Clonal patterns were not associated with the types of skin lesions or histopathological features. The transcription analysis did not detect RAG1 in any skin lesions.

Conclusions and clinical relevance: The present study is the first to report clonal heterogeneity in canine ECTCL that was not associated with the clinical or histopathological features of skin lesions. The results obtained also suggested that clonal heterogeneity originated not in the skin.

Background: Recently, the use of disinfectants to treat bacterial skin diseases in dogs has garnered attention from the perspective of preventing the spread of antibiotic-resistant bacteria. Ozone water is a disinfectant that combines high antibacterial efficacy and safety; however, there have been no reports verifying its effects on skin barrier function in dogs.

Objectives: This study aimed to verify the antibacterial properties and effects of ozone water on skin barrier function in dogs.

Animals: Four beagles for the antibacterial test and six beagles for the barrier function test.

Materials and methods: Purified water, 3 mg/L ozone water and 0.005% and 0.05% sodium hypochlorite were used as test products. Skin bacteria were collected 5 min after a single application of each and cultured to measure the bacterial counts. Trans-epidermal water loss (TEWL) and skin surface hydration (SSH) were measured before and after application once a day for 2 weeks. Additionally, the proliferation of canine epidermal keratinocytes (CPEK) was examined after a 5-min incubation with the test products.

Results: Ozone water and 0.05% sodium hypochlorite significantly reduced the number of skin bacteria. None of the test products worsened TEWL and SSH values. Sodium hypochlorite completely inhibited the proliferation of CPEK, while ozone water did not.

Conclusions and clinical relevance: Ozone water has an antibacterial effect on canine skin comparable to that of 0.05% sodium hypochlorite, but does not inhibit keratinocyte proliferation in vitro. Thus, ozone water has the potential to be used as a safe and effective disinfectant for canine skin.

Background: Skin diseases in sheep are important animal health and production problems, especially in wool-producing sheep.

Hypothesis/objectives: To document the type, signalment, associations and prevalence of skin disease in a referral hospital population.

Animals: Case population at a university veterinary medical teaching hospital.

Materials and methods: Retrospective study by searching computerised medical records of sheep examined between 1 January 1986 and 1 January 2021.

Keywords: 'alopecia, Arcanobacterium pyogenes, Corynebacterium, Demodex, dermatitis, Dermatophilus, dermatophyte, ectoparasite, examination, fibre damage, foot rot, fungus, interdigital necrobacillosis, itching, lice, Malassezia, melanoma, mite, pruritus, rubbing, scabies, skin, SCC, squamous cell carcinoma, Staphylococcus, Trueperella pyogenes, wool break, wool loss'.

Results: Two thousand and two records, totalling 11,799 sheep, had the age, breed and sex reported. Older sheep were more likely to present with skin disease (p < 0.0001; standard deviation 36.6 ± 1.15 confidence interval). The American Merino, East Friesian, Rambouillet, Suffolk and Shetland breeds were at higher risk of developing skin disease (p < 0.0001). Males, whether rams or wethers, were more likely to present with skin disease than ewes (p = 0.0019). Owing to the lack of dermatological examination reported, the four largest flocks (a total of 7,892 sheep) were excluded from disease analysis. Of the remaining 3,907 sheep, 299 (7.6%) had skin disease recorded. The most common diagnoses made were pododermatitis, bacterial abscesses, squamous cell carcinoma and myiasis. Fifty-five of 299 sheep were presented primarily for nonskin disease.

Conclusions and clinical relevance: Clinicians should include a dermatological examination in sheep regardless of the reason for presentation.

Background: Intradermal allergen testing (IDT) and allergen-specific immunotherapy (ASIT) remain underrated in feline dermatology.

Hypothesis/objectives: The objectives of this retrospective study were to report the results of IDT and the effects of ASIT on the medication needs in a population of 158 cats diagnosed with feline atopic skin syndrome (FASS).

Materials and methods: FASS was diagnosed after the exclusion of other pruritic conditions. IDT was performed under sedation/anaesthesia in 158 cats; in 136 of them, intravenous fluorescein and a Wood's lamp were used to facilitate interpretation. The medication scores were compared between cats with and without ASIT over a 1-year follow-up period.

Results: IDT was interpretable in 153 cats (97%) of which no specific sensitisation could be detected in 53 cases (35%). Among the remaining 100 (65%) cats, polysensitisation and monosensitisation were observed in 78 and 22 cases, respectively. Cats were sensitised to house dust mites (HDM; 74%) including Dermatophagoides farinae (67%) and D. pteronyssinus (27%); storage mites (SM; 44%) including Tyrophagus putrescentiae (27%), Acarus siro (32%) and Lepidoglyphus destructor (8%); moulds (7%); grasses (18%); weeds (19%); tree pollens (19%); and fleas (17%). ASIT was initiated in 78 of 100 cats, and a 1-year follow-up period was available for 42. ASIT had no effect in 11 cats (26%). In the remaining 31 cats (74%), ASIT was associated with a significant reduction (≥ 30%) in medication scores.

Conclusions and clinical relevance: ASIT is associated with a sparing effect in a significantly greater number of treated cats than untreated ones.

Background: Malassezia pachydermatis (MP) is implicated in severe dermatitis and otitis externa (OE) of companion animals and recently gained attention for its increasing resistance to azole compounds. For this reason, developing novel therapeutic strategies is of great interest. In a previous work, we used reference yeast isolates to evaluate several compounds bearing acyl/selenoureido moieties and primary/secondary sulfonamide groups for antifungal activity through organic selenium and carbonic anhydrase inhibition.

Objectives: This work aimed to evaluate the antifungal efficacy of eight selenoureido compounds on 36 clinical MP isolates from dogs, compared to selected azoles, notably ketoconazole (KCZ), miconazole (MCZ) and fluconazole (FCZ).

Materials and methods: MIC assays of 5g, 7a, 7c, 7k, 8c, 10c, 11b, 11f, KCZ, MCZ and FCZ were performed on 36 MP field isolates isolated from dogs affected by dermatitis and/or OE in which yeast aetiology was suspected. Minimum 50% and 90% inhibitory concentrations (MIC₅₀ and MIC₉₀) were calculated. MP identification was confirmed with a nested PCR for the internal transcribed spacer region of the rRNA gene.

Results: Overall, the MIC₅₀ of the tested compounds on MP field isolates was higher than the MICs obtained on reference MP DSM 6172. Although KCZ showed the lowest MIC₅₀ value, compounds 5g, 7a and 7k showed lower MIC₅₀s than MCZ and FCZ. Five clinical isolates showed a MIC on azoles >MIC₉₀. Compounds 7a (four of five), 10c (three of five) and 8c (three of five) showed lower MIC values on these isolates compared to the tested azoles, suggesting good activity in phenotypically azole-resistant MP.

Conclusions and clinical relevance: Considering the increasing azole resistance of the Malassezia genus, selenoureido compounds could represent a potential topical treatment for dog skin and ear mycotic infections.

Background: Ichthyoses represent a heterogeneous group of cornification disorders characterised by epidermal scaling.

Objectives: To describe the clinical, histopathological and genetic analysis of a Labrador retriever with nonepidermolytic ichthyosis, and the results of a population screening for a newly detected PNPLA1 genomic duplication.

Animals: Two 7-year-old male littermates, 531 population samples.

Materials and methods: Clinical and histopathological analysis, whole genome sequencing and digital PCR-based genotyping were performed.

Results: Generalised scaling and histological laminar orthokeratotic hyperkeratosis confirmed the ichthyosis diagnosis on Dog 1. Dog 2 showed mild clinical signs possibly associated with allergies and not ichthyosis. The genome of Dog 1 was sequenced and compared to 1469 genetically diverse control genomes. The analysis identified a 6099-bp duplication spanning three internal exons of the PNPLA1 gene, which is predicted to result in an altered C-terminal tail of the protein, NP_001277038.2:p.(E558Lfs*17). Dog 2 had a heterozygous genotype and carried one copy of the duplicated PNPLA1 allele. Of the screened 531 additional Labrador retrievers, 491 were homozygous wild-type, 36 were heterozygous carriers and four carried the duplication in a homozygous state.

Conclusions and clinical relevance: Previously identified PNPLA1 variants cause autosomal recessive ichthyosis in golden retrievers and humans. Given the well-established function of PNPLA1, the identified genomic duplication represents a likely candidate causal variant for the observed ichthyosis in the examined Labrador retriever. This is the first report of a new form of autosomal recessive ichthyosis in Labrador retrievers, which provides the basis for genetic testing.

Background: Canine interdigital furunculosis (CIF) is a complex, relapsing inflammatory condition, typically complicated by deep bacterial infections requiring prolonged systemic antibiotics.

Hypothesis/objectives: This split-body study, where dogs acted as their own control, evaluated whether the adjunctive use of fluorescent light energy (FLE) could shorten the time to clinical resolution of CIF and minimise systemic antimicrobial use.

Animals: Thirty-five client-owned dogs with signs of interdigital furunculosis in at least two paws.

Materials and methods: This prospective, single-blinded, randomised, split-body multicentre clinical trial treated dogs with systemic antibiotics based on bacterial culture and sensitivity. One paw per dog was randomly selected using a coin-toss method for weekly FLE application, while the other paw served as a control. Dogs were scored every 2 weeks over 56 days on two parameters: a global lesion score (including haemorrhagic vesicles, fistulae with draining tracts, crusts and ulcers) and neutrophils engulfing bacteria score (NES, 0-4). Time to clinical resolution and lesion scores were assessed and compared between groups.

Results: At Day (D)28 and D56, the FLE group showed significantly more healed paws (50% and 88%, p = 0.021) compared to the control (17% and 54%, p = 0.008). The median time to clinical resolution was shorter for the FLE group (35 days) compared to the control group (56 days, p = 0.017). No difference in NES score was observed between groups.

Conclusions and clinical relevance: This blinded, randomised, split-body clinical trial demonstrated that FLE is an effective adjunctive therapy for CIF. It reduces the time to clinical resolution and increases the resolution rate while minimising the need for antibiotics.

Background: Keratinised tissues, such as nails and claws, accumulate hormones over time; the claws' hormone concentrations are being explored as potential biomarkers. Timelines for hormone deposition can be established if claw growth rates are known. Hormone concentration within cat claws has been recently evaluated, yet the growth rates of cat claws remain unknown.

Hypothesis/objectives: To estimate the growth rate of adult cats' claws, we hypothesised that front claw growth rates would differ from those of rear claws.

Animals: Seventeen client-owned, indoor, neutered, adult cats.

Materials and methods: Cats' claws were clipped and then measured lengthwise. Claws were repeatedly measured over time with repeat claw trims after approximately 1 month, followed by repeat measurements. Average claw growth rates were calculated for three digit groups: forelimb digit 1, forelimb digits 2-5 (front) and hind limb (rear). Growth rates of the front compared to the rear and digit 1 were compared through linear mixed effects regression modelling.

Results: The daily mean claw growth rates were 0.13 mm for front and digit 1, and 0.08 mm for rear. The growth rate of rear claws was significantly lower (p < 0.001) than for front claws; rear claws grew, on average, 0.04 mm less per day than front claws.

Conclusions and clinical relevance: Our study provides the first measurement of claw growth rates in cats. The significantly slower growth rate of rear claws compared to front claws should be considered when evaluating metabolites within cat claws.

Background: The submission of bacterial cultures to an off-site microbiology laboratory is standard practice in veterinary medicine. The effects of a transport delay on culture results from canine pyoderma samples remain unknown.

Hypothesis/objectives: The first objective was to evaluate the reliability of Staphylococcus species isolation by aerobic bacterial cultures from samples collected from canine pyoderma when transported to a microbiology laboratory on the collection day. The second objective was to evaluate the effect of a 72-h transport delay on Staphylococcus spp. isolation and antibiotic susceptibilities.

Animals: Thirty client-owned dogs with pyoderma that presented to a private dermatology clinic were included in this study.

Materials and methods: Three sterile culturettes were used to sequentially swab one pyoderma lesion per dog. Two samples were transported on the collection day (immediate cultures), while one was refrigerated for 72 h before transportation to a microbiology laboratory. Ninety cultures were performed and the results compared.

Results: There was good reliability of Staphylococcus spp. isolation between the immediate cultures. There was no significant difference in the Staphylococcus spp. isolation, Staphylococcus spp. methicillin resistance or Staphylococcus pseudintermedius antibiotic susceptibilities with a 72-h transport delay, with the exception of chloramphenicol susceptibilities.

Conclusions and clinical relevance: Cultures from canine pyoderma can have good reliability of Staphylococcus spp. isolation when submitted to a microbiology laboratory on the collection day. Cultures that are delayed at 4°C for ≤72 h can still have reliable results regarding S. pseudintermedius isolation and susceptibilities.