Atopic Dogs Research Articles

Investigation into the Effects of Allergen Exposure and Topical Vinegar and Water Spray on Skin Barrier Parameters in Atopic Dogs.

Increased skin pH and transepidermal water loss (TEWL) are documented in atopic people and dogs but no study has investigated how these parameters change during an allergy flare. Our primary aim was to challenge atopic beagles to dust mites and measure pH and TEWL during a flare of atopic dermatitis and correlate these parameters to clinical signs. A secondary aim was to evaluate in a randomized placebo-controlled study whether the daily application of 50/50 vinegar spray improves clinical signs and affects skin parameters despite the allergen challenge. Fifteen atopic dogs were challenged epicutaneously twice weekly for 2 weeks with allergen application on the inguinal and medial thigh areas. The severity of dermatitis was scored daily (CADESI-03). TEWL and pH were measured daily on the inguinal and medial thigh areas. A repeated measures ANOVA showed the significant effect of time, with increased pH (p < 0.0001), TEWL (p < 0.0001), and CADESI (p < 0.0001) during allergen challenge. Significant positive correlations were found between CADESI and pH (r = 0.3556; p < 0.0001), CADESI and TEWL (r = 0.36; p < 0.0001), and pH and TEWL (r = 0.45; p < 0.0001). Daily application of 50/50 vinegar did not improve dermatitis, pH, and TEWL compared to the control treatment. It can be concluded that both pH and TEWL are markers of disease severity in canine atopic dermatitis.

Investigation on the in vitro effects of resveratrol on peripheral blood mononuclear cells harvested from healthy and atopic dogs

Canine atopic dermatitis (AD) is a common skin disease. Many therapeutic options are available to decrease inflammation and ameliorate pruritus. However, those treatments are associated with side effects, a long lag phase for efficacy, or high expense. Natural plant extracts have been identified as possible, safer alternatives to traditional anti-inflammatory and antipruritic drugs. Resveratrol has been revisited as a new, possible alternative for its numerous beneficial properties. The purpose of this study was to evaluate the in vitro effects of resveratrol on peripheral blood mononuclear cells (PBMC) harvested from healthy and atopic privately-owned dogs.The PBMC harvested from nine healthy and 11 atopic dogs were isolated and exposed to four concentrations (1.5-9 μg/mL) of resveratrol both with or without phytohemagglutinin stimulation. After 24 h cytotoxicity, host defense peptides (HDPs), as well as oxidative stress (catalase and superoxide dismutase), and pro-inflammatory cytokines were assessed. Cytotoxicity was not observed in either group under any experimental conditions. An increase in catalase was only seen in healthy PBMC after exposure to low concentrations of resveratrol (p ≤ 0.03). Resveratrol did not show any effect on canine HDPs. Compared to baseline, there was a significant reduction in monocyte chemotactic protein-1 and interleukin-6 after exposure to 9 μg/mL of resveratrol in unstimulated healthy (p = 0.029) and stimulated atopic (p = 0.0075) PBMC. In conclusion, these data confirm the overall lack of cytotoxicity of resveratrol on healthy and atopic PBMC at the tested concentrations. However, at the concentrations tested, there was only a minimal effect of resveratrol on the secretion of HDPs and pro-inflammatory cytokines.

Long-term tapering regimen use of oclacitinib for the control of pruritus in an atopic dog

Long-term tapering regimen use of oclacitinib for the control of pruritus in an atopic dog

Rapid induction of allergen-blocking IgG in dogs vaccinated with plant-based, Der f 2-expressing bioparticles.

Allergen-carrying virus-like particles are effective and safe means of allergen immunotherapy (AIT) in rodent models. To study the development of allergen-blocking immunoglobulin (Ig)G in dogs injected with Der f 2-carrying enveloped plant-based bioparticles (eBPs). Laboratory beagle dogs were injected intradermally (ID) or subcutaneously (SC) with Der f 2-eBP three times at 2-week intervals. A basophil mediator release assay was used to compare the reactivity of Der f 2-eBPs to that of recombinant Der f 2. Allergen-specific IgG serum levels were determined by immunoblotting and ELISA. The allergen-blocking potential of postvaccination IgG was assessed by Pet Allergy Xplorer (PAX) macroarray and basophil mediator release inhibition assays. The amount of Der f 2 eBPs needed to induce basophil activation was 1000-fold higher than that of the soluble natural allergen. In both immunisation groups, eBP injections caused no adverse events and induced Der f 2-specific IgG, first detected on Day (D)14 and peaking on D41. The co-incubation of sera with a Der f 2-IgE-rich canine serum pool resulted in a mean PAX inhibition of 70% (ID) to 80% (SC) on D41. For both groups, the inhibition of basophil mediator release reached 75% on D28 and D41. The percentage inhibition of PAX and mediator release correlated significantly with Der f 2 IgG levels. Intradermal and subcutaneous injections of Der f 2-eBPs were safe and increased Der f 2-specific IgG. The clinical benefit of immunotherapy will be evaluated in future trials enrolling atopic dogs allergic to house dust mites.

Long-term use of lokivetmab in dogs with atopic dermatitis.

Lokivetmab, a caninised monoclonal antibody against interleukin (IL)-31, is an effective treatment for the pruritus associated with canine atopic dermatitis (cAD). To investigate the efficacy and safety of lokivetmab during long-term treatment defined as at least three consecutive lokivetmab injections in atopic dogs under field conditions. To assess individual factors influencing treatment outcome and adverse events. 150 dogs with cAD. Medical records of dogs treated with lokivetmab were reviewed, and owners and/or veterinarians were contacted as needed for follow-up. A decrease of the pruritus Visual Analog Scale (PVAS) score by ≥2 or a PVAS score ≤2 after treatment was considered as treatment success. Logistic regression was used to investigate the influence of a variety of factors on outcome: type of cAD (food versus environment), age at first lokivetmab administration, disease chronicity, dosage and/or secondary infection. Any adverse event that occurred during the study period was recorded. Lokivetmab reduced the PVAS score with long-term use (p < 0.01); the success rate was 53 of 69 total dogs (77%). The probability of treatment failure decreased with increasing treatment duration. None of the factors investigated influenced the treatment outcome. Twelve dogs of 150 (8%) showed adverse events such as gastrointestinal signs or lethargy. Lokivetmab appears to be an effective and safe long-term anti-itch therapy for dogs with cAD.

Treatment of moderate-to-severe canine atopic dermatitis with modified-release mycophenolate (OKV-1001): A pilot open-label, single-arm multicentric clinical trial.

Mycophenolate is an immunomodulating agent successfully used for the treatment of moderate-to-severe atopic dermatitis (AD) in people. Mycophenolate is an effective steroid-sparing treatment option for use in dogs with inflammatory skin diseases. To evaluate whether once-daily modified-release mycophenolate (OKV-1001) is safe and effective for treating moderate-to-severe canine AD. Client-owned atopic dogs (n = 9) were enrolled. In an open-label multicentre pilot study, OKV-1001 (30 mg/kg every 24 h) was given orally for ≤84 days. Concomitant tapering doses of glucocorticoids were administered up to Day (D)28. Clinicians assessed Canine Atopic Dermatitis Extent and Severity Index, 4th iteration (CADESI-04) on D0, D14, D28, D56 and D84. Body weight and clinical pathological parameters were measured at baseline and at the end of the study. Treatment with OKV-1001 combined with glucocorticoids significantly reduced the severity of AD within two weeks in seven of nine (77.8%) dogs. The mean percentage change from baseline in the CADESI-04 score was 29% (p = 0.009) at D14 (n = 9), 39% (p = 0.008) at D28 (n = 9) and 49% (p = 0.03) at D56 (n = 7) at which point glucocorticoids had been withdrawn. In two dogs the improvement in CADESI-04 was 62% and 23% (respectively) on D84. No significant adverse events including clinical pathological findings were reported. Modified-release mycophenolate (OKV-1001) may represent a promising alternative treatment option for dogs with moderate-to-severe AD. The safety and efficacy profile of OKV-1001 will need to be established in larger, placebo-controlled clinical trials.

Evaluation of the correlation of serological and intradermal allergen testing with clinical history in 29 dogs with atopic dermatitis.

Limited information exists about the correlation between clinical history and positive serum (SAT) and intradermal allergen test (IDAT) results in atopic dogs. To evaluate the correlation between clinical history and SAT/IDAT results in atopic dogs. Twenty-nine client-owned dogs with nonseasonal atopic dermatitis with or without seasonal exacerbation were enrolled. IDAT, SAT (immunoglobulin (Ig)M antibody capture enzyme-linked immunosorbent assay [MacELISA] with bromelain CCD inhibitor) and clinical information collected in a questionnaire regarding seasonal variations in pruritus affecting the dogs were performed on the same day. Two independent investigators (Inv A and Inv B) recorded IDAT results. The kappa coefficients agreement for positive IDAT scores between Inv A and B was substantial. The agreement between IDAT and SAT results at different ELISA absorbance units (EAU) cut-offs (>79 and ≥300) was slight and fair for both investigators, respectively. A higher agreement was observed between IDAT and SAT (≥300 EAU) than between IDAT and SAT (>79 EAU) with the exception of mite and flea allergens. There was a statistically significant association between clinical history and positive IDAT results for seasonal allergens (Inv A and Inv B, p = 0.016). There was no significance between positive SAT results and clinical history. Five (IDAT) and 12 of 13 (SAT) atopic dogs without clinical seasonal exacerbation showed positive results for seasonal allergens. The agreement between IDAT and SAT ≥300 EAU results was fair and the agreement between IDAT and SAT >79 EAU results was slight for all allergens. Only positive IDAT results significantly correlated with clinical history.

A prospective study evaluating the correlation between local weather conditions, pollen counts and pruritus of dogs with atopic dermatitis.

Canine atopic dermatitis (cAD) is a hereditary, generally pruritic and predominantly T-cell-driven inflammatory skin disease, involving an interplay between skin barrier abnormalities, allergen sensitisation and microbial dysbiosis. The individual immunological response is predominantly against environmental allergens, including mite antigens; mould spores; and pollen from grasses, trees and weeds. Airborne pollens show fluctuating patterns during the year. The aim of this prospective study was to evaluate the influence of local pollen concentrations and weather conditions on the clinical signs of atopic dogs, and to investigate any possible correlations with the results of intradermal testing (IDT). Thirty-seven privately owned atopic dogs in Bavaria were surveyed from 1 April to 30 November 2021. Owners were asked to record pruritus using a validated Visual Analog Scale (PVAS) score and the weekly medication of their dog. Furthermore, weather data, including pollen count, rainfall, relative humidity, hours of sunshine and temperature from the dog's location were collected daily. Of the evaluated parameters, only humidity and medication scores correlated positively with the PVAS scores of the atopic dogs. There was no correlation between specific pollen counts and PVAS scores of dogs with positive IDT reactions to that pollen. The outcome of this study highlights the importance of a careful interpretation of positive IDT results in dogs with cAD and questions the validity of airborne pollen trap methodology in representing pollen exposure for dogs at ground level.

Efficacy of Chlorhexidine Impregnated Wipes for the Local Dysbiosis in Atopic Dogs: A Multicentric Prospective Study.

(1) Background: Dysbiosis is frequently observed in Canine Atopic Dermatitis (CAD). Antimicrobial treatment may be necessary to treat flare ups and the use of topical treatments is beneficial to prevent the development of bacterial resistance. Wipes are an easy way to apply antiseptic agents on the skin. The aim of this study was to evaluate the benefits of 3% chlorhexidine impregnated wipes (Pyoskin® wipes, MP Labo, France) on local areas of dysbiosis in dogs with CAD. (2) Methods: A total of 20 dogs suffering from CAD presented with localised areas of dysbiosis were included in this study. Affected areas were cleansed with the daily application of chlorhexidine wipes once a day for 14 days. Follow-up visits were scheduled after one and two weeks. Clinical signs (lesions and pruritus), dysbiosis scored by cytological counts (cocci and Malassezia) and investigator and owner global appreciation were evaluated. (3) Results: A statistically significant decrease in clinical scores and cytological counts were observed as soon as D7 and until D14. Both owner and investigator appreciation were considered high (4) Conclusions: The use of chlorhexidine impregnated wipes is a useful and easy way to manage localised dysbiosis in atopic dogs and allows limiting of systemic medication to prevent bacterial resistance.

Evaluation of the Impact of Near-Infrared Multiwavelength Locked System Laser Therapy on Skin Microbiome in Atopic Dogs.

Photobiomodulation (PBM) is a newly adopted consensus term to replace the therapeutic application of low-level laser therapy. It has been suggested that PMB influences the microbiome which, in turn, has increasingly been shown to be linked with health and disease. Even though the use of PBM has also grown dramatically in veterinary medicine, there is still a lack of evidence supporting its effect in vivo. Our objective was to investigate the impact of a dual-wavelength near-infrared laser source (Multiwavelength Locked Laser System, MLS®) on the skin microbiome in atopic dogs. Twenty adult-client-owned atopic dogs were enrolled in the study. The dogs were treated with MLS® laser therapy on one half of the abdominal region, whereas the contralateral side was left untreated and served as a control. Skin microbiome samples were collected before and after MLS® treatments, and then subjected to NGS-based ITS and 16S rRNA analysis. The results showed that while microbiome composition and diversity were not significantly affected, PBM could play a role in modulating the abundance of specific bacterial species, in particular Staphylococcus, that represent a major skin pathogenic strain. To the best of the authors' knowledge, this is the first study to investigate the potential impact of MLS® laser therapy on the skin microbiome in atopic dogs.

A placebo-controlled, double-blind study evaluating the effect of orally administered polyunsaturated fatty acids on the oclacitinib dose for atopic dogs.

Supplementation of polyunsaturated fatty acids (PUFA) enables dose reduction of prednisolone and ciclosporin in canine atopic dermatitis (cAD). To determine if oral administration of PUFA reduces the dose of oclacitinib in cAD. Twenty-two client-owned dogs with cAD receiving oclacitinib. Dogs received a fish oil product (PUFA) or paraffin oil (placebo) for 16 weeks. Owners adjusted the oclacitinib dose according to daily pruritus assessments. On Day (D)0, D56 and D112, Canine Atopic Dermatitis Extent and Severity Index, fourth iteration (CADESI-04), pruritus Visual Analog Scale (PVAS), quality-of-life score (QoL), Global Assessment (GA), quality-of-coat (QoC) and adverse events were recorded. Mean daily oclacitinib dose was significantly reduced in the PUFA group from 0.51 ± 0.20 mg/kg/24 h (D0) to 0.19 ± 0.14 mg/kg/24 h (D85-112; p < 0.00001) and not in the placebo group (D0: 0.70 ± 0.33 mg/kg/24 h; D85-112: 0.53 ± 0.35 mg/kg/24 h, p = 0.5422). CADESI-04 did not change over time or differ between groups. PVAS was significantly lower in the PUFA group (2.8 ± 1.5) compared to placebo (4.2 ± 1.6) at D112 (p = 0.0375). QoL and QoC improved only in the PUFA group (QoL: D0: 20 ± 7, D112: 12 ± 5, p = 0.0057; QoC: D0: 0 ± 0.5, D112: 1 ± 0.5, p = 0.0410). GA on D112 was higher in the PUFA group (p = 0.008). No adverse events were observed. Oral supplementation of PUFA allowed dose reduction of oclacitinib and improved PVAS, QoL, QoC and GA. The use of PUFA is recommended and was safe in the atopic study dogs receiving oclacitinib.

Bacterial microbiota and proinflammatory cytokines in the anal sacs of treated and untreated atopic dogs: Comparison with a healthy control group.

The pathogenesis of anal sacculitis has not been extensively investigated, although atopic dogs seem to be predisposed to the disease. The aim of this study was therefore to characterize and compare the bacterial microbiota and pro-inflammatory cytokines in the anal sacs of dogs from three groups (healthy dogs, untreated atopic dogs and atopic dogs receiving antipruritic treatment or allergen-specific immunotherapy) in order to determine whether changes could be at the origin of anal sacculitis in atopic dogs. Bacterial populations of anal sac secretions from fifteen healthy dogs, fourteen untreated and six treated atopic dogs were characterized by sequencing the V4 region of the 16S rRNA gene using Illumina technology. Proinflammatory cytokines were analyzed with the Luminex multiplex test. Community membership and structure were significantly different between the anal sacs of healthy and untreated atopic dogs (P = 0.002 and P = 0.003, respectively) and between those of untreated and treated atopic dogs (P = 0.012 and P = 0.017, respectively). However, the community structure was similar in healthy and treated atopic dogs (P = 0.332). Among the proinflammatory cytokines assessed, there was no significant difference between groups, except for interleukin 8 which was higher in the anal sacs of untreated atopic dogs compared to treated atopic dogs (P = 0.02), and tumor necrosis factor-alpha which was lower in the anal sacs of healthy dogs compared to treated atopic dogs (P = 0.04). These results reveal a dysbiosis in the anal sacs of atopic dogs, which may partially explain the predisposition of atopic dogs to develop bacterial anal sacculitis. Treatments received by atopic dogs (oclacitinib, desloratadine and allergen-specific immunotherapy) shift the microbiota of the anal sacs towards that of healthy dogs. Further studies are required to identify significant cytokines contributing to anal sacculitis in atopic dogs.

Blocking cross-reactive carbohydrate determinant-specific IgE improves serum allergy testing reliability in atopic dogs.

Blocking cross-reactive carbohydrate determinant-specific IgE improves serum allergy testing reliability in atopic dogs.

Update on the role of genetic factors, environmental factors and allergens in canine atopic dermatitis.

Canine atopic dermatitis (cAD) is a common, complex and multifactorial disease involving, among others, genetic predisposition, environmental factors and allergic sensitisation. This review summarises the current evidence on the role of genetic and environmental factors and allergic sensitisation in the pathogenesis of cAD since the last review by ICADA in 2015. Online citation databases and proceedings from international meetings on genetic factors, environmental factors and allergens relevant to cAD that had been published between 2015 and 2022 were reviewed. Despite intensive research efforts, the detailed genetic background predisposing to cAD and the effect of a wide range of environmental factors still need more clarification. Genome-wide association studies and investigations on genetic biomarkers, such as microRNAs, have provided some new information. Environmental factors appear to play a major role. Lifestyle, especially during puppyhood, appears to have an important impact on the developing immune system. Factors such as growing up in a rural environment, large size of family, contact with other animals, and a nonprocessed meat-based diet may reduce the risk for subsequent development of cAD. It appears that Toxocara canis infection may have a protective effect against Dermatophagoides farinae-induced cAD. House dust mites (D. farinae and D. pteronyssinus) remain the most common allergen group to which atopic dogs react. Currently, the major allergens related to D. farinae in dogs include Der f 2, Der f 15, Der f 18 and Zen 1. Canine atopic dermatitis remains a complex, genetically heterogeneous disease that is influenced by multiple environmental factors. Further, well-designed studies are necessary to shed more light on the role of genetics, environmental factors and major allergens in the pathogenesis of cAD.

Indoor particulate matter induces epigenetic changes in companion atopic dogs

The prevalence of atopic dermatitis (AD) is increasing and environmental factors are receiving attention as contributing causes. Indoor air pollutants (IAPs), especially particulate matter (PM) can alter epigenetic markers, DNA methylation (DNAm). Although DNAm-mediated epigenetic changes have been reported to modulate the pathogenesis of AD, their role at high risk of exposure to PM is still unclear. The study investigated the effects of exposure to IAPs in the development of AD and epigenetic changes through DNAm in companion atopic dogs that share indoor environment with their owners. Dogs were divided into two groups: AD (n = 47) and controls (n = 21). The IAPs concentration in each household was measured for 48 h, and a questionnaire on the residential environment was completed in all dogs. Eighteen dogs with AD and 12 healthy dogs were selected for DNAm analysis. In addition, clinical and immunological evaluations were conducted. The concentrations of PM2.5, PM10, and volatile organic compounds (VOCs) were significantly higher in the AD group. Moreover, there were more significant methylation differences in the LDLRAD4, KHSRP, and CTDSP2 genes in connection with PM10 in AD group compared to the controls. The degree of methylation of the LDLRAD4 and CTDSP2 genes was also correlated with related protein productions. The present study revealed that exposure to high indoor PM can cause epigenetic development of AD by methylation of the LDLRAD4, KHSRP, and CTDSP2 genes in dogs. Under the concept of "One Health," improving indoor environments should be considered to prevent the development of AD.

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.

Cross-reactive carbohydrate determinants in atopic and healthy dogs and their influence on allergy test specificity.

The selection of allergens for immunotherapy in atopic dogs is often based on serum allergy testing. Cross-reactive carbohydrate determinants (CCDs) are common structures in plant and insect allergens that reportedly induce polysensitisation, reduce agreement between intradermal and serum tests and complicate allergen selection. Thirty-four dogs with diagnosed atopic dermatitis and 10 healthy dogs were included in the study. An intradermal test was conducted in atopic dogs, and serum samples from allergic and healthy dogs were analysed for allergen-specific immunoglobulin E (IgE) before and after inhibition of detectable anti-CCD-IgE antibodies. Anti-CCD-IgE antibodies were not found in any of the healthy dogs and no polysensitisation to plant and insect allergens was detected. The agreement between intradermal and serum allergy test results in the atopic dogs with anti-CCD-IgE antibodies improved from slight to fair after blocking the anti-CCD-IgE antibodies. In addition, blocking clearly reduced polysensitisation to plant allergens but not to acarid allergens. Only a limited number of healthy dogs were tested in this study. A gold standard for determining the clinical relevance of IgE sensitisation does not exist. Inhibition of anti-CCD-IgE antibodies seems to be of importance to improve serum test specificity for allergen-specific IgE in atopic dogs in relation to intradermal allergy testing.

Non-controlled, open-label trial to assess clinical and immunological parameters in atopic dogs feeding monoprotein grain free diet versus a standard grain diet

Canine atopic dermatitis (cAD) is a common inflammatory skin disease that is treated with medicines or allergen-specific immunotherapy. An improvement diet can help treatment of cAD. The purpose of this study was compare two diets on clinical and immunological parameters in atopic dogs without food hypersensitivity. Diet A, a commercial based on rice, was offered to 22 atopic dogs during 30 days and Diet B (grain free, rich in salmon) was given to 8 atopic dogs. Clinical scores were assessed by CADESI-4 and PVAS at the beginning (T0) and at the end of the study (T30). CD4+ and CD8+ were measured in PBMCs, and serum cytokines (TNF-α, IL-10, IL-31 and IL-34) were determined. Both diets decreased CADESI-4 score and Diet A decreased PVAS score (p < 0.05). There were no statistical significant differences between diets at T30 for CD4+ and CD8+. A decrease in the IL-31 concentrations and increase in IL-10 levels (p < 0.05) was observed with Diet A at T30. There were no differences between any of the two diets when the other results at T0 and T30 were compared for any of the parameters analysed. In conclusion, the results indicate that dietary intervention had not influence on cellular component of the immune system, but a positive effect was observed on IL-31, IL-10 serum levels for Diet A. Further studies are needed to enrich dietary components of the food for atopic dogs without food hypersensibility to help improvement the management of the cAD.

Immunolocalization and Expression of JAK1 and JAK3 in the Skin of Dust Mite-Sensitive Beagle Dogs before and after Allergen Exposure.

Janus kinase (JAK) pathways have emerged as targets of treatment, yet localization and expression of JAK1 and JAK3 in canine atopic skin have not been studied. This study aimed to compare the localization and expression of JAK1 and JAK3 in the skin of atopic dogs before and after allergen exposure. Skin biopsies taken from atopic beagles sensitized to house dust mites (HDM) before (D0) and after four weeks (D28) of allergen exposure were stained. Staining was subjectively scored by examiners unaware of the source of the slides. Image J was used for the semiquantitative assessment of staining intensity. JAK1 and JAK3 staining was epidermal and dermal. JAK1 staining was cytoplasmic, primarily found in basal keratinocytes and dermal cells, while JAK 3 was nuclear (all epidermal levels and on dermal inflammatory cells). Epidermal thickness was significantly higher on D28 than on D0 (p < 0.0001). For JAK1, epidermal staining divided by epithelial thickness was significantly lower on D28 (p = 0.0002) compared to D0. For JAK3 staining, intensity in the dermis was significantly higher on D28 (p = 0.0405) compared to D0. We conclude that decreased expression of JAK1 in the epidermis and increased expression of JAK3 in the dermis of atopic dogs occur after allergen exposure.

Pilot study to determine the concordance between skin prick and intradermal test (IDT) reactivity to environmental allergens in atopic dogs using IDT as the gold standard.

Prick testing is widely used as the first-line in vivo test for environmental allergens in people owing to its noninvasive nature and speed of performance. To determine concordance between skin prick testing (SPT) and intradermal testing (IDT) reactivity to environmental allergen mixes in dogs with atopic dermatitis (cAD). Forty client-owned dogs with cAD. Skin prick testing (GREER Pick System; Stallergenes Greer) and IDT were performed on 40 dogs using seven glycerinated and aqueous environmental allergen mixes, respectively (tree, grass and weed pollens, house dust mites and three mould mixes). Reactions for IDT and SPT were evaluated both subjectively and objectively (mean wheal diameter; MWD) and compared to saline and histamine controls. Using IDT as the gold standard, with subjective scoring, SPT was 47.0% sensitive [95% confidence interval (CI) 36.0%-58.7%], 92.1% specific (95% CI 87.6%-95.3%) and agreement was moderate (79%, Cohen's kappa = 0.424). The positive predictive value of SPT was 36% and negative predictive value was 95%. Objective and subjective scores had only fair agreement. Skin prick testing with allergen mixes was specific yet poorly sensitive as compared to IDT. For both IDT and SPT, 95% (38 of 40) dogs failed to react to an allergen mix, despite showing a positive reaction to at least one component. Future studies comparing SPT and IDT should test individual allergens rather than mixes to prevent the dilution of individual components, which may have resulted in false negatives.