Investigation on the Effect of Dose, Frequency and Duration of Allergen Exposure on Development of Staphylococcal Infections in a Chronic Model of Canine Atopic Dermatitis

Canine atopic dermatitis (CAD) is chronic and frequently complicated by Staphylococcal infections. Understanding the role of allergen dose, frequency and duration of exposure in triggering infections requires a model. Most models elicit acute inflammation and do not mimic real-life disease. Here we describe the effects of allergen exposures on development of infections in a model of chronic CAD. Diagnosis of pyoderma was based on clinical signs and consistent cytology. Study 1 evaluated the role of duration of exposure keeping the daily dose constant (25 mg/day). The one-week protocol involved three exposures, 3 days in a row. The one-month protocol involved twice-weekly challenges for 4 weeks. The three-month protocol involved twice-weekly challenges for 12 weeks. Study 2 evaluated different daily doses while keeping constant the total weekly dose (25 mg) and duration (3 weeks). Low-dose used 5 mg/day for 5 days, each week. High-dose used 12.5 mg/day twice-weekly. In Study 1, the longer the exposure, the more dogs developed pyoderma (6/9 in the three-month study, 2/9 in the one-month and 0 in the one-week). In Study 2, low-dose daily exposure caused more infections (5/8) than high-dose infrequent exposure (0/8). It is concluded that low-grade, daily exposure for a long time is most relevant for development of staphylococcal infections.

Efficacy of Phototherapy With 308-nm Excimer Light for Skin Microbiome Dysbiosis and Skin Barrier Dysfunction in Canine Atopic Dermatitis

The management of canine atopic dermatitis, an allergic skin disorder, is challenging. To investigate the effect of phototherapy using a 308-nm excimer light as a topical treatment for canine atopic dermatitis, 10 dogs with canine atopic dermatitis and 10 with non-allergic skin were enrolled in this study. Phototherapy was applied every 7 days for a total of 2 months. The skin microbiome, skin barrier function, and clinical outcomes were evaluated after phototherapy. Phototherapy significantly changed the composition of the skin microbiome of dogs with atopic dermatitis and significantly increased the relative abundance of the phyla Actinobacteria and Cyanobacteria. It significantly alleviated the clinical signs of canine atopic dermatitis without serious adverse effects. Transepidermal water loss, as a measure of skin barrier function, significantly decreased after phototherapy. In addition, phototherapy increased microbial diversity and decreased the relative abundance of Staphylococcus pseudintermedius associated with the severity of canine atopic dermatitis. These results suggest that the excimer light therapy is a suitable and safe therapeutic option for canine atopic dermatitis, which is also a spontaneous animal model of atopic dermatitis.

Prospective Evaluation of the Use of Lokivetmab in Dogs With Atopic Dermatitis in Brazil

Background: Lokivetmab (Cytopoint®, Zoetis) is a caninized anti-IL-31 monoclonal antibody licensed for treating clinical manifestations of canine atopic dermatitis in varying degrees of severity. The objective of this 30-day prospective study was to evaluate the level of improvement in cases of atopic dermatitis after the application of lokivetmab, using the Canine Atopic Dermatitis Extent and Severity Index (CADESI-4) variables, Visual Analogue Scale (VAS) of pruritus, owner assessment of the condition, and incidence of adverse events. A total of 110 animals recruited from two private clinics in the State of São Paulo each received 2 mg of lokivetmab/kg of body weight by subcutaneous injection on day 0. Dogs were observed by owners who provided reports of their observations by telephone or e-mail on days 2 and 14 and were observed by clinicians on day 30. Results: Baseline mean VAS of pruritus was 7.68 (median = 7), decreasing to 3.82 (median = 2) by day 2 (P<0.001). CADESI-4 variables decreased from 36.5 at baseline to 16.3 on day 30 (P<0.001). Reports of treatment responses submitted by owners and evaluation of CADESI-4 variables after treatment were significantly similar (P<0.001). Owners rated the response to treatment as good to excellent for 75% of the dogs. Adverse events, including vomiting, diarrhea, and/or lethargy, were observed in 18 dogs (16.4%). All events were transient, and none required treatment. Conclusions: Based on findings in this study, lokivetmab was determined to provide a rapid and effective response for control of canine atopic dermatitis. Lokivetmab was well tolerated with only mild and transient adverse events observed.

Effects of Feeding a Hypoallergenic Diet with a Nutraceutical on Fecal Dysbiosis Index and Clinical Manifestations of Canine Atopic Dermatitis

Background: an imbalance of the intestinal microbiota can cause health problems in the gastrointestinal tract and in other organs. Canine Atopic Dermatitis (CAD) is a genetically predisposed, inflammatory and pruritic allergic skin disease with multifactorial etiology and multimodal treatment. The aim of this study was to assess the effect of a nutraceutical product on Dysbiotic Index (DI) and the skin lesions of atopic dogs. Methods: a nutraceutical product was administered to 32 dogs with CAD. The product was associated with a standardized hypoallergenic diet for 60 days; the dietary regimen continued for 120 days, while ongoing therapies remained unchanged. Values of Visual Analogic Scale (VAS), Canine Atopic Dermatitis Lesional Index (CADLI) and DI were evaluated on day 0, 60, 120. Results: all the 32 dogs showed a statistically significant decrease (p < 0.001) to V60 of VAS and CADLI, which persisted and increased to V120 when diet alone was continued. The decrease in the DI value was also statistically significant (p < 0.001). Conclusion: the intake of nutraceutical associated with diet resulted in a decrease in the index of intestinal dysbiosis, with an improvement in the subjective severity of cutaneous lesions.

Local and Systemic Changes in Lipid Profile as Potential Biomarkers for Canine Atopic Dermatitis

Lipids play a critical role in the skin as components of the epidermal barrier and as signaling and antimicrobial molecules. Atopic dermatitis in dogs is associated with changes in the lipid composition of the skin, but whether these precede or follow the onset of dermatitis is unclear. We applied rapid lipid-profiling mass spectrometry to skin and blood of 30 control and 30 atopic dogs. Marked differences in lipid profiles were observed between control, nonlesional, and lesional skin. The lipid composition of blood from control and atopic dogs was different, indicating systemic changes in lipid metabolism. Female and male dogs differed in the degree of changes in the skin and blood lipid profiles. Treatment with oclacitinib or lokivetmab ameliorated the skin condition and caused changes in skin and blood lipids. A set of lipid features of the skin was selected as a biomarker that classified samples as control or atopic dermatitis with 95% accuracy, whereas blood lipids discriminated between control and atopic dogs with 90% accuracy. These data suggest that canine atopic dermatitis is a systemic disease and support the use of rapid lipid profiling to identify novel biomarkers.

Clinical effects of 2 commercially available diets on canine atopic dermatitis

Objective Canine atopic dermatitis (CAD) is a common skin disease in dogs. Prior studies were able to determine beneficial effects of essential fatty acids (EFA) on the clinical signs of CAD. The aim of this study was set to evaluate the effects of a newly designed, EFA-enriched diet on the clinical signs of CAD compared to another EFA-enriched diet. Materials and methods In this prospective, randomized, double-blinded study, 31 privately owned dogs with atopic dermatitis received either the control diet (diet A, Hill’s Prescription Diet™ d/d™ Salmon & Rice, n = 17) or the test diet (diet B, Veterinary HPM™ Dermatology Support D1, Virbac, n = 14) for 12 weeks. At the beginning of the study as well as after 4, 8 and 12 weeks, skin lesions and pruritus were evaluated via validated scores and the administered medication was documented. At the same time, the dogs’ coat quality was evaluated via a distinct scoring system. In both groups, a total of 7 dogs each completed the entire study. Results After 12 weeks, there was a mild improvement in lesion scores, pruritus and coat quality with both diets. Clinical relevance In this study, both diets improved the patients’ skin lesions pruritus and coat quality.