Veterinary dermatology最新文献

Background: Polyoxyethylene hydrogenated castor oil (HCO ethoxylates) is a nonionic surfactant used as an excipient for ointments and injections in human and veterinary drugs. Several polyethylene glycol (PEG) derivatives can be obtained depending on the number of moles of ethylene oxide (EO). HCO ethoxylates have the potential to cause anaphylactoid reactions. There is little published information about these types of reactions in dogs.

Objective: To determine the potential for HCO-ethoxylate-containing drugs to cause anaphylactoid reactions in dogs, employing intradermal testing (IDT) with various concentrations of HCO ethoxylates (HCO-25, -40, -60 and -80).

Animals: Four healthy male laboratory dogs.

Materials and methods: We performed IDT with drugs containing HCO ethoxylates and HCO ethoxylates alone to determine threshold concentrations. The IDT scores and threshold concentrations were compared. Analysis of skin biopsies from IDT sites was used to measure the percentage of degranulated mast cells. The effect of histamine at IDT sites was investigated by pre-treatment with an antihistamine.

Results: All HCO-ethoxylate-containing drugs caused a wheal-and-flare reaction. The threshold concentrations (0.001% and 0.00001%) of each HCO-ethoxylate depended on the number of moles of EO (p < 0.05). Mast cell degranulation was enhanced by all HCO ethoxylates. The HCO-60-induced reaction was suppressed by an oral antihistamine.

Conclusions and clinical relevance: The threshold concentration can serve as a consideration for developing safe new drug formulations and for clinical decision-making around using drugs containing PEG derivatives. IDT is useful to predict the risk of adverse effects. Antihistamines could demonstrate a prophylactic effect.

Background: Intravenous administration of interleukin (IL)-31 in healthy dogs has been used as a model to assess antipruritic drugs. However, there is no known in-depth characterisation of pruritic behaviours, and the repeatability of the IL-31-induced pruritus in the individual dogs is currently unknown.

Objectives: To evaluate the immediate/delayed pruritus responses and the pruritic behaviours observed in the IL-31-induced pruritic model in healthy dogs after repeated IL-31 injections.

Animals: Fifteen healthy laboratory beagles.

Methods: All dogs were video-recorded for 270 min after two intravenous recombinant IL-31 injections (1.75 μg/kg) and vehicle (phosphate-buffered saline, control) injections, respectively; interventions were randomised and performed with a 2 week wash-out period. Two blinded investigators reviewed the pruritic behaviours of all video recordings.

Results: Both canine IL-31 (IL-31_01, IL-31_02) injections significantly increased pruritic seconds and categorical minutes ('YES'/'NO' behaviour per discrete 1 min interval) in healthy dogs compared with both vehicle groups (Vehicle_01, Vehicle_02). The second intravenous canine IL-31 (IL-31_02) administered 14 days after the first IL-31 injection induced a significant increase in pruritic seconds (p = 0.021) and not pruritic categorical minutes (p = 0.231). An increase in pruritic seconds was observed in both IL-31 groups in the first 30 min post-administration, while there was no significant difference between IL-31 and vehicle groups.

Conclusions and clinical relevance: In conclusion, intravenous IL-31 reproducibly induces itch responses in dogs. Future evaluations of the canine IL-31 pruritic model should assess total pruritic behaviours in seconds rather than using a biased 'YES/NO' behaviour per 1 min scoring system.

Background: Norway spruce (Picea abies) resin-based products are used in human medicine. A resin-based otic rinse also could be useful in supportive care of canine otitis externa (COE), yet information on its antimicrobial effect against canine pathogens or ototoxicity is lacking.

Objectives: To investigate the antimicrobial properties and ototoxicity of a commercial resin-based otic product.

Materials and methods: Antimicrobial effect was evaluated using a standardised challenge test on Staphylococcus pseudintermedius, Corynebacterium auriscanis, Pseudomonas aeruginosa, Escherichia coli, Malassezia pachydermatis, and Streptococcus halichoeri strains to measure reduction in growth after 24 h exposure to the product. Effect on cell morphology was investigated by exposing S. pseudintermedius, C. auriscanis, P. aeruginosa and M. pachydermatis to the product in 20% and 100% (v/v) concentrations for 6, 24 and 48 h, and evaluating cells by transmission (TEM) and scanning (SEM) electron microscopy. An in vitro microbial kill-rate assay also was performed. Auditory brain stem response test, clinical evaluation and postmortem histological evaluation of ear canals were undertaken on experimental guinea pigs treated with the test product or saline controls.

Results: The product showed >log 5 growth reduction for all strains in the challenge test. TEM and SEM images showed clear changes in the cells' inner structures and deterioration of cells, and 100% (v/v) test product exposure induced microbial killing in 1-2 h. Ototoxicity was not detected in guinea pigs.

Conclusions and clinical relevance: The product may be an option in supportive care of COE because of antimicrobial effects and lack of ototoxic properties in a guinea pig model.

Background: Otitis is characterised by inflammation of one or more of the structures of the ear. At present, to confirm or exclude otitis media (OM), it is most often necessary to perform a computed tomography (CT) scan or magnetic resonance imaging. Inflammation is an immune defence response found in many conditions that can be detected and tracked by measuring biological markers of inflammation as the Canine C-reactive protein (CRP).

Objectives: The objective of this study was to determine whether CRP measurement is useful as an adjunctive diagnostic tool in dogs with otitis and whether elevated concentrations correlated with disease severity/presence of OM.

Animals: Twenty-four client-owned dogs were recruited over 1 year.

Materials and methods: The dogs were divided into three groups: chronic or recurrent otitis externa (CO), otitis media (OM) and H (healthy). The dogs with otitis underwent a CT scan of the head, measurement of the plasma CRP concentration and evaluation of a 0-3 Otitis Index Score 3 (OTIS3 score).

Results: No dog (0%) in group H had an increased CRP value, compared to 20% in the CO group (one of five dogs) and 23% in the OM group (3 of 13 dogs). Plasma CRP concentrations show a statistically significant positive relationship with the OTIS3 score (p = 0.04).

Conclusion and clinical relevance: Plasma CRP concentration is not reliable as a discriminatory tool in cases of otitis, although there is a trend for elevation in cases with more severe disease. However, a larger study may provide a statistically more reliable correlation between the severity of OM and CRP concentrations.

Background: Diascopy is a point-of-care diagnostic test used to differentiate skin erythema due to vascular dilation from haemorrhage. In the veterinary literature, only a handful of diseases have been described to be associated with a negative (nonblanching) diascopy result, and histological investigation of haemorrhage has been inconsistent.

Objectives: Retrospective study to undertake a histopathological investigation of canine, nonblanching erythematous dermatoses for the presence or absence of haemorrhage and vascular changes.

Materials and methods: Skin biopsies from dogs presented with moderate-to-severe nonblanching erythema were evaluated histologically. Additionally, clinical data about each patient were analysed.

Results: Twenty cases were identified with nonblanching erythema. Diagnoses included vasculopathy (n = 6), canine eosinophilic dermatitis (n = 3), cutaneous epitheliotropic T-cell lymphoma (n = 2), and one case each of sterile granuloma and pyogranuloma syndrome, German shepherd dog pyoderma, multiple mast cell tumours, haemangiosarcoma, exfoliative cutaneous lupus erythematosus, canine leishmaniosis with sebaceous adenitis, sebaceous adenitis with concurrent dermatophytosis, calcinosis cutis and canine atopic dermatitis with insect-bite reaction. One or more vascular changes were present in all 20 cases and included perivascular oedema, endothelial swelling and neutrophilic infiltration of vessel walls. Haemorrhage was identified in 17 of 20 cases (85%). Three cases without dermal haemorrhage were calcinosis cutis, sebaceous adenitis with dermatophytosis and canine atopic dermatitis with insect-bite reaction.

Conclusions and clinical relevance: Negative diascopy was associated with haemorrhage and vascular pathological findings in the majority of cases, yet not all. Haemorrhage was identified histologically in all diseases previously reported as nonblanching as well as in a few additional diseases.

Proliferative, lymphocytic, infundibular mural folliculitis and dermatitis have been reported in six female Labrador retrievers from North America. This is the first report of the disease outside North America, describing the clinical and histopathological diagnosis and dermoscopic aspect of the verrucous plaques, treatment and co-morbidities in a female Labrador retriever dog.

Background: Canine middle ear effusion (MEE) is usually asymptomatic, being an incidental finding when computed tomography or magnetic resonance imaging (MRI) of the head is performed for other reasons unrelated to otic disease. The clinical relevance of the presence of material in the tympanic bulla (TB) remains uncertain, and more detail about its prevalence and appearance in MRI are required.

Objective: To assess the prevalence of presence of material within the TB of French bulldogs (FB) with no clinical signs suggestive of otitis (externa, media or interna) that underwent high-field MRI for other medical reasons.

Animals: Two hundred fifty-two TB of 126 FB were included in this study.

Materials and methods: Nonexperimental retrospective study in which MRI images were evaluated by a board-certified veterinary radiologist.

Results: Fifty-eight per cent of the dogs had material in the TB lumen (46% of the TB) and 59% were bilaterally affected. The signal intensity of this material related to the grey matter was variable on T1w and mainly hyperintense on T2w sequences.

Conclusion and clinical relevance: FB are predisposed to MEE. This is important when assessing imaging studies of TB of FB with chronic otitis externa, as high percentage of cases may have concurrent MEE. MRI findings in FB with MEE are characterised by a hyperintense signal to the grey matter on T2w in most cases and variable on T1w sequences.

Background: No reports have compared the clinical therapeutic efficacy of fluconazole and itraconazole in canine Malassezia dermatitis.

Objectives: The study aimed to compare the clinical therapeutic efficacy of fluconazole and itraconazole and to evaluate the adverse effects of fluconazole in canine Malassezia dermatitis.

Animals: Sixty-one client-owned dogs with Malassezia dermatitis.

Materials and methods: The enrolled animals were randomly divided into groups receiving 5 mg/kg fluconazole (5FZ), 10 mg/kg fluconazole (10FZ) or 5 mg/kg itraconazole (5IZ). The drugs were orally administered once daily for 28 days. Cytological examination, clinical index score (CIS), pruritus Visual Analog Scale (PVAS) evaluation and blood analysis (for 5FZ only) were performed on Day (D)0, D14 and D28.

Results: On D14, significant reductions in mean yeast count (MYC), CIS and PVAS were observed in the 5FZ (n = 20, p < 0.01), 10FZ (n = 17, p < 0.01) and 5IZ (n = 16, p < 0.05) groups. In all three groups, a significant reduction (p < 0.001) in MYC, CIS and PVAS expression was observed on D28. There was no significant difference in the percentage reduction of MYC, CIS and PVAS among the groups. Moreover, there was a significant difference (p < 0.05) in each group between D14 and D28, except for the percentage reduction in MYC in the 10FZ and 5IZ groups. No adverse effects of fluconazole were observed in the 5FZ or 10FZ groups.

Conclusions and clinical relevance: This study indicates that 5FZ and 10FZ are as effective as itraconazole in canine Malassezia dermatitis.