The ACVD task force on canine atopic dermatitis (XV): fundamental concepts in clinical diagnosis

PDE4D and miR-203 are promising biomarkers for canine atopic dermatitis

BACKGROUND

Canine atopic dermatitis (CAD) is a common genetically predisposed, inflammatory, and pruritic skin disorder that affects dogs globally. To date, there are no specific biomarkers available to diagnose CAD, and the current diagnosis is based on a combination of criteria including patient history, clinical signs, and exclusion of other relevant differential diagnoses.

METHODS AND RESULTS

We examined the gene expression of phosphodiesterase 4D (PDE4D) in peripheral blood mononuclear cells (PBMCs), as well as miR-203 and miR-483 in plasma, in three groups: healthy dogs, CAD dogs, and other inflammatory pruritic skin diseases (OIPSD) such as pemphigus foliaceus, scabies, cutaneous lymphoma, and dermatophytosis. Our results showed that PDE4D gene expression in the CAD group is statistically higher compared to those in the healthy and OIPSD groups, suggesting PDE4D may be a specific marker for CAD. Nevertheless, no correlation was found between PDE4D gene expression levels and the lesion severity gauged by CAD severity index-4 (CADESI-4). We also showed that miR-203 is a generic marker for clinical dermatitis and differentiates both CAD and OIPSD inflammatory conditions from healthy controls.

CONCLUSIONS

We show that PDE4D is a potential marker to differentiate CAD from non-atopic healthy and OIPSD while miR-203 may be a potential marker for general dermatologic inflammation. Future study of PDE4D and miR-203 on a larger scale is warranted.

A Randomized Controlled Trial to Evaluate the Impact of a Novel Probiotic and Nutraceutical Supplement on Pruritic Dermatitis and the Gut Microbiota in Privately Owned Dogs

Pruritic dermatitis (PD) is a common presentation of canine allergic skin diseases, with diversity in severity and treatment response due to complex etiopathogenesis. Evidence suggests the gut microbiota (GM) may contribute to the development of canine allergies. A 10-week double-blind randomized controlled trial evaluated a novel probiotic and nutraceutical blend (PNB) on clinical signs of skin allergy, health measures, and the GM of privately owned self-reported pruritic dogs. A total of 105 dogs were enrolled, with 62 included in pruritus and health analysis and 50 in microbiome analysis. The PNB supported greater improvement of owner-assessed clinical signs of PD at week 2 than the placebo (PBO). More dogs that received the PNB shifted to normal pruritus (digital PVAS10-N: <2) by week 4, compared to week 7 for the PBO. While a placebo effect was identified, clinical differences were supported by changes in the GM. The PNB enriched three probiotic bacteria and reduced abundances of species associated with negative effects. The PBO group demonstrated increased abundances of pathogenic species and reduced abundances of several beneficial species. This trial supports the potential of the PNB as a supplemental intervention in the treatment of PD; however, further investigation is warranted, with stricter diagnostic criteria, disease biomarkers and direct veterinary examination.

Efficacy of Allogeneic and Xenogeneic Exosomes for the Treatment of Canine Atopic Dermatitis: A Pilot Study

Canine atopic dermatitis (CAD) is a genetically predisposed inflammatory pruritic skin disease. The available treatments for CAD have several adverse effects and vary in efficacy, indicating the need for the development of improved treatments. In this study, we aimed to elucidate the therapeutic effects of allogeneic and xenogeneic exosomes on CAD. Six laboratory beagle dogs with CAD were randomly assigned to three treatment groups: control, canine exosome (cExos), or human exosome (hExos) groups. Dogs in the cExos and hExos groups were intravenously administered 1.5 mL of cExos (5 × 1010) and hExos (7.5 × 1011) solutions, respectively, while those in the control group were administered 1.5 mL of normal saline three times per week for 4 weeks. Skin lesion score and transepidermal water loss decreased in cExos and hExos groups compared with those in the control group. The exosome treatments decreased the serum levels of inflammatory cytokines (interferon-γ, interleukin-2, interleukin-4, interleukin-12, interleukin-13, and interleukin-31) but increased those of anti-inflammatory cytokines (interleukin-10 and transforming growth factor-β), indicating the immunomodulatory effect of exosomes. Skin microbiome analysis revealed that the exosome treatments alleviated skin bacterial dysbiosis. These results suggest that allogeneic and xenogeneic exosome therapy may alleviate CAD in dogs.

The safety of rush immunotherapy in the management of canine atopic dermatitis-230 cases

BACKGROUND

The duration of the induction phase of allergen-specific immunotherapy conventionally is a period of several weeks, during which the volume of an allergen solution, administered by injection, is gradually increased until the maintenance dose is reached. In rush immunotherapy (RIT), the induction period is abbreviated to achieve a faster improvement in clinical signs of atopic dermatitis (AD) compared to conventional immunotherapy.

OBJECTIVE

The aim of this retrospective study was to evaluate the safety of RIT in 230 dogs with AD and report any adverse effects (AE).

ANIMALS

Two hundred thirty client-owned dogs.

MATERIALS AND METHODS

Medical records of dogs receiving RIT between 2012 and 2021 were analysed and observed AE were investigated. All dogs underwent RIT following a protocol of subcutaneous allergen extract injections, given hourly with an incrementally increasing volume from 0.1 to 1.0 mL.

RESULTS

Adverse effects were documented in 6 of 230 (2.6%) dogs. Five of these dogs (2.2%) showed mild gastrointestinal signs (1 of 5 vomiting, 4 of 5 diarrhoea) and one patient an increase in body temperature by 1.5°C. These occurred at different stages of the RIT protocol. All AE were graded as mild and self-limiting.

CONCLUSIONS AND CLINICAL RELEVANCE

Based on these data, supervised RIT in dogs appears to be a safe procedure to achieve the maintenance dose of allergen immunotherapy earlier with infrequent and mild AE.

A randomised, double-blinded comparison between subcutaneous rush and intralympathic allergen immunotherapy induction in atopic dogs

BACKGROUND

Atopic dermatitis (AD) is one of the most common skin diseases in small animal practice. Allergen immunotherapy (AIT) is the only curative treatment for the disease, and oral, subcutaneous and intralymphatic administration of allergens are commonly employed.

OBJECTIVES

To compare the efficacy of AIT following an induction phase with intralymphatic injections (ILIT) or rush immunotherapy (RIT).

ANIMALS

Fifty privately owned dogs with AD.

MATERIALS AND METHODS

In a double-blinded study, dogs were randomly assigned to either four monthly ILIT of allergen extract or RIT with five injections administered subcutaneously at hourly intervals on the first day. They were assessed by validated scores; Canine Atopic Dermatitis Lesion Index (CADLI) and pruritus Visual Analog Scale (PVAS) at the beginning of the study and after 1, 3, 6 and 12 months. The latter were performed daily for 7 days before each revisit. Medication scores and a total clinical score were calculated and compared between each group and time point.

RESULTS

There was no significant difference in CADLI and PVAS scores, or CADLI and medication scores between groups at any of the time points. A significant improvement with both ILIT and RIT was seen in total and pruritus scores, respectively. An owner global assessment of good-to-excellent treatment efficacy was seen in 40% of the dogs; total scores improved by 27% and 35% in the RIT and ILIT group, respectively. Adverse effects were not seen.

CONCLUSIONS AND CLINICAL RELEVANCE

Induction of AIT can be conducted either as RIT or ILIT with no loss in efficacy.

Associations Between Atopic Dermatitis and Anxiety, Aggression, and Fear-Based Behaviors in Dogs

The goal of this study was to determine if anxiety, aggression, and fear-related behaviors are more common in pruritic dogs with atopic dermatitis than nonpruritic, healthy dogs. One hundred forty-one pruritic dogs >1 yr of age with a clinical diagnosis of atopic dermatitis and a >3 mo history of pruritus were recruited. Dog owners completed a behavioral survey (canine behavioral assessment and research questionnaire) and a pruritus scale (pruritus visual analog scale). Pruritic, atopic dogs showed significant increases in fear- and anxiety-related behaviors as well as aggression compared with a large control group of healthy dogs. Stranger-directed aggression, owner-directed aggression, familiar-dog aggression, dog-directed fear, nonsocial fear, touch sensitivity, excitability, and attention-seeking behaviors were all increased in the study group. Trainability was decreased in the study group. Chronically pruritic dogs experience fear and anxiety and are more likely to display aggression. This is an important welfare issue for these animals. Early recognition of the behavioral derangements that can be associated with chronic pruritic skin disease could allow early intervention with a multidisciplinary approach for these patients, thus improving patient and owner quality of life and long-term treatment outcomes.

Detection of chicken DNA in commercial dog foods

BACKGROUND

These days the number of potential food allergens is very large, but chicken is one of the most common allergens in dogs. Elimination diet is one of the clinical tools for the diagnosis of allergies and allergy tests are not very reliable. The restriction diet is most commonly carried out by feeding pet foods, relying on the ingredients on the label to select an elimination diet not containing previously eaten foods. Unfortunately, mislabeling of pet food is quite common. The purpose of this study was to determine the absence or presence of chicken DNA using both qualitative and quantitative polymerase chain reaction (PCR) analysis methods in dry and wet maintenance complete pet foods for adult dogs. Results were used to verify the declared composition on the labels.

RESULTS

Eleven out of fifteen (73%) dog foods were produced as declared by the manufacturer, two of which showed the presence of chicken protein as stated on the label. The remaining nine foods contained amounts of chicken DNA below 1%, consistent with declarations that no chicken was added in the composition. Four of tested dog foods (27%) were not produced consistently with the declaration on the packaging. Two dog foods (one dry and one wet) did not contain the claimed chicken protein. In two foods the addition of chicken DNA was detected at the level of over 2% and almost 6%, respectively.

CONCLUSIONS

In this study, we focused on one of the most commonly undeclared animal species on the label-chicken protein-and performed DNA analyzes to investigate possible contamination and mislabeling. The results showed some inaccuracies. However, most of them are trace amounts below 1%, which proves compliance with the label. Our results showed that undeclared animal species can be as common as missing an animal protein declared on the label. The conducted research indicates that both dry and wet analyzed foods should not be recommended as a diagnostic tool in elimination tests, because it may result in false negative results. Over-the-counter maintenance foods for dogs should not be recommended for the diagnosis and treatment of food hypersensitivity.

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.

Detection of Serum Allergen-Specific IgE in Atopic Dogs Tested in Northern Italy: Preliminary Study

Canine atopic dermatitis (CAD) is a pruritic allergic skin disease associated with IgE-mediated hypersensitivity. IgE is detected using Serum Allergen-Specific IgE test (SAT) in order to identify allergens. The present study aims to identify the environmental allergens in atopic dogs living in Northern Italy using SAT. The screening SAT (sSAT), using a monoclonal antibody cocktail-based ELISA to identify indoor and outdoor allergens, was performed. In all positive samples, an anti-IgE monoclonal antibody ELISA test was performed to extend panel of allergens. Out of 117 selected dogs, 69 were included in the study; 71% were positive and 29% were negative to sSAT. Among the 49 positive sSAT, 53% were positive for both indoor and outdoor, 38.8% only for indoor, and 8.2% only for outdoor allergens. This is the first study on the frequency of allergens involved in CAD in Italy using SAT. IgE hypersensitivity in atopic dogs of Northern Italy is usually associated with indoor allergens, primarily house dust mites. Among the outdoor allergens, an important role was played by Rumex acetosa. Polysensitization also commonly occurs. Therefore, since the numerous factors affect the IgE positivity in CAD, specific panels for geographical areas should be considered and re-evaluated at time intervals.

A proposed medication score for long-term trials of treatment of canine atopic dermatitis sensu lato

BACKGROUND

The use of concurrent medications is necessary in trials of treatment of canine atopic dermatitis. Our aim was to use the best available evidence to construct and then to validate a medication score (MS) formula that will estimate the impact of concurrent medications on trial outcomes.

METHODS

Trials of 15 interventions were scrutinized to find those that were consistent in terms of specific medication, administration route and dosage regimen. A MS was constructed in five steps, starting from assigning a score of 1 for each day on oral prednisone, prednisolone or methylprednisolone at 0.5-1.0 mg/kg. The MS score was validated using the clinical records of 35 dogs with atopic dermatitis that had been treated for a period of 12 ± 2 weeks with six of these medications and compared with a previously published non-validated MS.

RESULTS

A MS could be assigned to eight treatments, six of which had been administered to the 35 dogs. A positive correlation was seen with the previously published MS and a negative correlation with changes in lesional and pruritus scores.

CONCLUSION

This MS may be a useful tool in new studies evaluating the efficacy of treatments in canine atopic dermatitis.

Staffordshire Bull Terriers in the UK: their disorder predispositions and protections

Background

The Staffordshire Bull Terrier is a popular dog breed in the UK but there is limited reliable evidence on disorder predispositions and protections within the breed. Using anonymised veterinary clinical data from the VetCompass™ Programme, this study aimed to identify common disorders with predisposition and protection in the Staffordshire Bull Terrier. The study hypothesised that Staffordshire Bull Terriers would have higher odds of aggression compared with non-Staffordshire Bull Terriers.

Results

The clinical records of a random sample of dogs of all types were reviewed to extract the most definitive diagnoses for all disorders existing during 2016. A combined list from the 30 most common disorders in Staffordshire Bull Terriers and the 30 most common disorders in non-Staffordshire Bull Terriers was generated. Multivariable logistic regression was used to report the odds of each of these disorders in 1304 (5.8%) Staffordshire Bull Terriers compared with 21,029 (94.2%) non-Staffordshire Bull Terriers. After accounting for confounding, Staffordshire Bull Terriers had significantly increased odds of 4/36 (11.1%) disorders compared to non-Staffordshire Bull Terriers with highest odds for seizure disorder (OR 2.06; 95% CI 1.24 to 3.40; p = 0.005). Conversely, Staffordshire Bull Terriers had reduced odds of 5/36 (13.9%) disorders, with lowest odds for patellar luxation (OR 0.15; 95% CI 0.04 to 0.61; p = 0.008). There was no significant difference in the odds of aggression between Staffordshire Bull Terriers compared with non-Staffordshire Bull Terriers (OR 1.09; 95% CI 0.75 to 1.58; p = 0.644).

Conclusions

This study provides a reliable evidence base of breed-specific disorder predispositions and protections that can be used by breeders to optimise breeding decisions. The findings can assist prospective owners of Staffordshire Bull Terriers to make informed decisions when acquiring a dog. From the relative number of predispositions to protections identified, there is no evidence that Staffordshire Bull Terriers have higher overall health problems than non-Staffordshire Bull Terriers.

Prevalence of positive reactions in intradermal and IgE serological allergy tests in dogs from South Australia, and the subsequent outcome of allergen-specific immunotherapy

OBJECTIVE

To determine the prevalence of positive allergen reactions in intradermal and IgE serological tests in dogs presenting to a dermatology referral centre in South Australia and the clinical efficacy of subsequent allergen-specific immunotherapy.

DESIGN

Retrospective study.

METHODS

Results from 108 intradermal allergy tests, 25 IgE serological assays and immunotherapy outcomes in 37 dogs were retrospectively analysed. Immunotherapy outcomes were determined as excellent, good, modest or failure using a global assessment of efficacy matrix which incorporated pruritus scores, lesion severity, medication requirements, and owner and clinician opinion.

RESULTS

The most common positive reactions in intradermal allergy tests were Red clover (59%), Dermatophagoides farinae (29%), Tyrophagus putrescentiae (28%), Yellow dock (25%) and Malassezia pachydermatis (24%). In the IgE serological tests, Yorkshire fog grass (40%), Yellow dock (36%), Kentucky bluegrass (36%) and T. putrescentiae (36%) were the most commonly reported positive results. The outcome of allergen-specific immunotherapy was judged to be excellent in 20% of dogs, good in 15%, modest in 18% and a failure in 47%.

CONCLUSION

As has been reported in other geographical areas, environmental mites and plant pollens frequently gave positive reactions in allergy tests in South Australia. However, the prevalence of individual allergen reactions differed between intradermal and IgE serological tests, with M. pachydermatis being identified as a common cause of hypersensitivity in intradermal tests but not in IgE serological assays. Immunotherapy was judged to be a beneficial treatment in 35% of dogs but was essentially unsuccessful in 65%.

West Highland White Terriers under primary veterinary care in the UK in 2016: demography, mortality and disorders

Background

The West Highland White Terrier (WHWT) is a relatively common breed in the UK, although Kennel Club registrations have declined in recent years. The VetCompass™ Programme collates de-identified clinical data from primary-care veterinary practices in the UK for epidemiological research. Using VetCompass clinical data, this study aimed to characterise the demography, longevity and common disorders of WHWTs under primary veterinary care in the UK.

Results

WHWTs comprised 6605/905,544 (0.7%) dogs under veterinary care during 2016 from 886 clinics. Mean adult bodyweight was 9.6 kg (standard deviation [SD] 1.8 kg). Males (10.1 kg, SD 1.8 kg) were heavier than females (9.0 kg, SD 1.6 kg) (P < 0.001). Median age was 7.8 years (interquartile range [IQR] 4.3–11.1). Median longevity was 13.4 years (IQR 11.0–15.0). Males (13.8 years) outlived females (12.9 years) (P = 0.045). The most common grouped causes of death were lower respiratory tract (10.2, 95% CI: 5.5–16.7), neoplastic (10.2, 95% CI: 5.5–16.7) and spinal cord disorder (7.8, 95% CI: 3.8–13.9). Overall, 71.5% WHWTs had > 1 disorder recorded during 2016. The most prevalent specific disorders were periodontal disease (15.7, 95% CI: 14.1–17.3), otitis externa (10.6, 95% CI: 9.3–12.0), overgrown nails (7.2, 95% CI: 6.2–8.4), allergic skin disorder (6.5, 95% CI: 5.5–7.7) and obesity (6.1, 95% CI: 5.1–7.2). The most prevalent grouped disorders were cutaneous (22.7, 95% CI: 20.9–24.6), dental (17.8, 95% CI: 16.2–19.6) and aural (12.3, 95% CI: 11.0–13.8). The median age of dogs affected with the 27 most common disorders varied from 6.7 (pododermatitis) to 13.9 years for cataracts.

Conclusions

These findings highlight that, despite a recent decline in popularity, WHWTs are still relatively common in the UK. Dental disease, ear disease, overgrown nails, allergic skin disorder and obesity were identified as common health issues within the breed. Cutaneous disorders were the most common disorder group in the breed but showed a lower prevalence than might be expected. These results can be used by breeders, veterinary practitioners and owners as an evidence base to predict, prevent and manage key health and welfare issues for WHWTs.

Pilot evaluation of Enterococcus faecium SF68 as adjunctive therapy for oclacitinib-responsive adult atopic dermatitis in dogs

OBJECTIVE

To evaluate the adjunctive effect of supplementation with Enterococcus faecium SF68 (FortiFlora; Purina Pro Plan Veterinary Diets) on oclacitinib (Apoquel, Zoetis) dose reduction, while maintaining or reducing the Pruritus Visual Analog Score and Canine Atopic Dermatitis Extent and Severity Index values in client-owned adult dogs with environmental atopic dermatitis.

MATERIALS AND METHODS

Enrolled dogs had exhibited control of atopic dermatitis on oclacitinib for at least 6 months before, and continuing throughout, the study. Dogs with non-seasonal pruritus were blindly randomised to receive either SF68 (1×10⁸ colony forming units/g orally twice daily) or placebo for 12 weeks. After 8 weeks of supplementation, oclacitinib dose was decreased by approximately 25%, aiming to maintain and reduce the clinical disease scores.

RESULTS

Supplementation with SF68 was associated with no difference in oclacitinib dose reduction versus placebo in 21 client-owned dogs with atopic dermatitis. Clinical disease scores were not different between groups at study completion.

CLINICAL SIGNIFICANCE

Further larger-scale studies are warranted to investigate optimal strain(s), dosing and duration of probiotic supplementation as an adjunctive strategy in management of canine atopic dermatitis.

Phosphodiesterase 4D, miR-203 and selected cytokines in the peripheral blood are associated with canine atopic dermatitis

Canine Atopic Dermatitis (AD) is a common complex and multifactorial disease involving immune dysregulation, genetic predisposition, skin barrier defects, environmental factors and allergic sensitization. To date, diagnosis of canine AD relies on a combination of patient history, clinical examination, allergy testing and response to diet trials/therapies with no reliable biomarkers available to distinguish AD from other diseases with similar clinical presentations. A handful of studies to identify potential biomarkers in the peripheral blood of AD dogs and healthy controls have been performed with some showing inconsistent and contradictory results. In this study, we, for the first time, report statistically significant increases in expression of phosphodiesterase 4D (PDE4D) gene in peripheral blood mononuclear cells (PBMCs) and miR-203 in plasma from AD dogs compared to healthy controls. In addition, we report a statistically non-significant change of the CD4⁺/CD8⁺ ratio, a dramatic decrease of three gene markers (PIAS1, RORA and SH2B1) as well as a panel of differential expression of cytokines in AD dogs in comparison to the healthy controls. Our study provides important insight into the complexities of canine AD, and further studies to verify the specificity of these findings for canine AD at a larger-scale are warranted.

Lesion distribution in cases of canine atopic dermatitis in South Australia

OBJECTIVE

To determine the lesion distribution patterns in different breeds of dogs affected by atopic dermatitis in South Australia.

METHODS

The presence or absence of erythematous skin lesions in 267 cases of canine atopic dermatitis (CAD) was recorded across 36 anatomical sites. Breeds represented by ≥ 9 dogs were included in the analysis. The percentage of dogs showing lesions at each of the body sites was calculated and illustrated on colour-coded diagrams. Variations in affected body sites within and between breeds were compared using Kruskal-Wallis ANOVA and Dunn's multiple comparison tests.

RESULTS

The prevalence of skin lesions at different body sites differed significantly both in the population as a whole and within breeds. The sites affected in ≥ 75% dogs were the dorsal and ventral aspects of the front and hind paws. The sites affected in 50-74% were the medial pinnae, axillae, ventral chest, abdomen and perineum. Sites affected in 25-49% of dogs included the face, periocular region and forelimb. Remaining body sites were affected in < 25% of dogs. Analysis at the breed level revealed some differences from this standard distribution pattern.

CONCLUSION

The results of this study confirmed the typical lesion distributions seen in CAD and highlighted some subtle differences in breeds commonly seen in South Australia. This will be useful for clinical practitioners in prioritising differential diagnoses for pruritic skin conditions.

The detection of house dust mite Dermatophagoides farinae, Der f 2 and Zen-1 allergen-specific immunoglobulin E antibodies in dogs with atopic Dermatitis in Malaysia

Canine atopic dermatitis (AD) is a chronic, inflammatory and pruritic allergic skin disease in dogs. House dust mites such as Dermatophagoides farinae are one of the known causative agents for the induction of canine AD worldwide. D. farinae protein Der f 2 is known as an important allergen involved in canine AD and recently, Zen-1 has also been identified as an allergenic protein. There is limited information on the prevalence and role of allergen sensitization to crude D. farinae extract (CDF), Der f 2 and Zen-1 among dogs diagnosed with AD in Malaysia. The aim of this study was to determine the proportion of CDF-, Der f 2- and Zen-1-specific reactive sera among dogs diagnosed with AD in Malaysia using an enzyme-linked immunosorbent assay (ELISA). Serum samples were collected from dogs diagnosed with AD from several veterinary clinics in Malaysia. The canine case records were retrieved and information on signalment, dermatological and non-dermatological histories, clinical presentation, food allergies, and exclusion of ectoparasitic, microbial and fungal skin infections were obtained through a survey form. All serum samples were evaluated to quantify the CDF-, Der f 2- and Zen-1-specific immunoglobulin E (IgE) levels. A total of 24.6%, 48.4% and 29.8% of dogs diagnosed with AD were positive for CDF-, Der f 2- and Zen-1-specific IgE, respectively. These results suggest that CDF-, Der f 2- and Zen-1 are important allergens that can contribute to AD in dogs in Malaysia, and serological testing can be performed to provide additional treatment options involving specific immunotherapies.

Agreement of serum allergen test results with unblocked and blocked IgE against cross-reactive carbohydrate determinants (CCD) and intradermal test results in atopic dogs

BACKGROUND

Tests for allergen-specific immunoglobulin E (IgE) are used to select allergens for immunotherapy in atopic dogs. Antibodies against cross-reactive carbohydrate determinants (anti-CCD IgE) have been identified in serum samples of atopic dogs. Their presence in humans is a known cause of clinically irrelevant polysensitization to plant allergens.

OBJECTIVES

To compare the results of an intradermal test (IDT) and a serum test for allergen-specific IgE, with and without blocking anti-CCD IgE, before testing in dogs.

ANIMALS

Thirty-one privately owned dogs with atopic dermatitis.

METHODS AND MATERIALS

Dogs were prospectively skin tested and their serum samples were analysed for anti-CCD IgE. An Fc-ε receptor-based serum test for allergen-specific IgE was performed with and without blocking anti-CCD IgE.

RESULTS

In dogs with negative anti-CCD IgE samples, the agreement between the results of the serum test and the IDT was substantial (κ = 0.71). Dogs with positive anti-CCD IgE samples (38.7%) showed no agreement between serum and skin testing (κ = -0.35), blocking anti-CCD IgE in those samples resulted in a fair agreement (κ = 0.43). Anti-CCD IgE positive sera had multiple positive results for grass and weed allergens, and blocking decreased them markedly.

CONCLUSION AND CLINICAL IMPORTANCE

Intradermal testing agreed best with serum testing in dogs with no detectable anti-CCD IgE. Sera containing anti-CCD IgE had no agreement with IDT. Test agreement was improved by blocking the anti-CCD IgE. Apparent serum test polysensitization to plant allergens was associated with anti-CCD IgE.

Atopic dermatitis in cats and dogs: a difficult disease for animals and owners

The purpose of this review article is to give an overview of atopic dermatitis in companion animals and of recent developments including knowledge on immunological background, novel treatment options and difficulties in disease management. The prevalence of hypersensitivities seems to be increasing. The pathogenetic mechanisms are not fully understood, yet multiple gene abnormalities and altered immunological processes are involved. In dogs and cats, the diagnosis of atopic dermatitis is based on history, clinical examination and exclusion of other differential diagnoses. Intradermal testing or testing for serum allergen-specific Immunoglobulin E is only used to identify allergens for inclusion in the extract for allergen immunotherapy. Symptomatic therapy includes glucocorticoids, ciclosporin, essential fatty acids and antihistamines. A selective janus kinase 1 inhibitor and a caninized monoclonal interleukin-31 antibody are the newest options for symptomatic treatment, although longterm effects still need to be assessed. The chronic and often severe nature of the disease, the costly diagnostic workup, frequent clinical flares and lifelong treatment are challenging for owners, pets and veterinarians. Patience and excellent communication skills are needed to achieve a good owner compliance and satisfactory clinical outcome for the animal.

Allergen immunotherapy in people, dogs, cats and horses - differences, similarities and research needs

In human patients with seasonal allergic rhinoconjunctivitis sensitized to grass pollen, the first successful allergen immunotherapy (AIT) was reported in 1911. Today, immunotherapy is an accepted treatment for allergic asthma, allergic rhinitis and hypersensitivities to insect venom. AIT is also used for atopic dermatitis and recently for food allergy. Subcutaneous, epicutaneous, intralymphatic, oral and sublingual protocols of AIT exist. In animals, most data are available in dogs where subcutaneous AIT is an accepted treatment for atopic dermatitis. Initiating a regulatory response and a production of "blocking" IgG antibodies with AIT are similar mechanisms in human beings and dogs with allergic diseases. Although subcutaneous immunotherapy is used for atopic dermatitis in cats, data for its efficacy are sparse. There is some evidence for successful treatment of feline asthma with AIT. In horses, most studies evaluate the effect of AIT on insect hypersensitivity with conflicting results although promising pilot studies have demonstrated the prophylaxis of insect hypersensitivity with recombinant antigens of biting midges (Culicoides spp.). Optimizing AIT using allergoids, peptide immunotherapy, recombinant allergens and new adjuvants with the different administration types of allergen extracts will further improve compliance and efficacy of this proven treatment modality.

A pilot study of total and allergen-specific IgE serum levels during anestrous, estrous and pregnancy in healthy female dogs

BACKGROUND

Allergen-specific IgE serology is used for the determination of sensitization status in dogs with atopic dermatitis; the influence of the female reproductive cycle on the results of such methods has not been studied in dogs.

OBJECTIVES

To compare the total and allergen-specific IgE of healthy bitches during anestrous, estrous and pregnancy.

ANIMALS

Eight privately owned, healthy bitches.

METHODS

Total and allergen-specific IgE levels were determined in eight bitches at three different time-points of their reproductive cycle: anestrous, estrous and pregnancy.

RESULTS

Total IgE was significantly decreased (median: 74%) in female dogs during pregnancy when compared to anestrous. In 14 of 216 (6%), allergen-specific IgE test results were variably positive and negative at different stages of the reproductive cycle. This variation, however, was not related to changes in total serum IgE levels.

CONCLUSIONS

Total IgE serum levels are reduced during pregnancy in female dogs. However, results of one allergen-specific IgE test did not appear to be markedly altered by the reproductive cycle in healthy bitches.

Evaluation of intraepidermal nerve fibres in the skin of normal and atopic dogs

BACKGROUND

Interest in intraepidermal nerve fibres (IENFs) is rising in human medicine, because variations in fibre density occur in some diseases and these neurites might contribute to disease pathogenesis. An increase in IENF density is seen in human atopic dermatitis (AD); there are no such data in atopic dogs.

OBJECTIVES

To compare the prevalence of IENFs in normal and atopic canine skin.

METHODS

Eight millimetre skin punch biopsies were taken from six sites of 25 healthy dogs without dermatitis and compared to lesional and nonlesional skin samples of dogs with AD (23 and 14 dogs, respectively). Thirty micrometre-thick paraffin-embedded sections were stained by indirect immunofluorescence for neuronal beta-3 tubulin. Only sections with detectable dermal nerves were then screened for the presence of IENFs.

RESULTS

IENFs were identified in all 25 normal nasal planum sections, but in only one biopsy collected from each of the normal canine haired skin (NCHS) sites. As there was no significant difference in IENF prevalence between NCHS areas, they were grouped together. The rate of detection of IENFs was significantly higher (one-tailed Fisher's test, P = 0.004) in lesional AD specimens (18 of 23; 78%) than in nonlesional AD (four of 14; 29%) and NCHS specimens (four of 111; 4%, P < 0.0001). The prevalence of IENF detection in nonlesional AD samples was significantly higher than in normal canine skin (P = 0.006).

CONCLUSIONS AND CLINICAL IMPORTANCE

IENFs are detected more commonly in canine AD than in normal haired skin; these results are comparable to those seen for human AD.

Canine atopic dermatitis: detailed guidelines for diagnosis and allergen identification

BACKGROUND

Canine atopic dermatitis (AD) is a common, genetically predisposed, inflammatory and pruritic skin disease. The variation in clinical presentations, due to genetic factors, extent of the lesions, stage of the disease, secondary infections, as well as resemblance to other non-atopic related skin diseases, can complicate a diagnosis of canine AD. A sub-group of the International Committee for Allergic Diseases in Animals (ICADA) was tasked with the development of a set of practical guidelines that can be used to assist practitioners and researchers in the diagnosis of canine AD. Online citation databases and abstracts from international meetings were searched for publications related to the topic, and combined with expert opinion where necessary. The final set of guidelines was approved by the entire ICADA committee.

RESULTS

A total of 81 publications relevant for this review were identified. The guidelines generated focus on three aspects of the diagnostic approach: 1. Ruling out of other skin conditions with clinical signs resembling, or overlapping with canine AD. 2. Detailed interpretation of the historical and clinical features of patients affected by canine AD. 3. Allergy testing by intradermal versus allergen-specific IgE serum testing.

CONCLUSIONS

The diagnosis of canine AD is based on meeting clinical criteria and ruling out other possible causes with similar clinical signs. Flea combing, skin scraping and cytology should be performed, where necessary, as part of a thorough work-up. Elimination diet trials are required for patients with perennial pruritus and/or concurrent gastrointestinal signs. Once a clinical diagnosis of canine AD is made, allergy testing can be performed to identify potential causative allergens for allergen-specific immunotherapy.

Proficiency monitoring of monoclonal antibody cocktail–based enzyme-linked immunosorbent assay for detection of allergen-specific immunoglobulin E in dogs

The purpose of our study was to document the continued comparative proficiency of different laboratories that perform a monoclonal antibody–based enzyme-linked immunosorbent assay (macELISA) for detection of allergen-specific immunoglobulin (Ig)E in dogs. Replicate samples of 18 different sera pools were independently evaluated in a single blinded fashion by each of 16 different operators functioning in 10 different laboratories. The average intra-assay variance among reactive assay calibrators in all laboratories was 6.0% (range: 2.7–16.1%), while the average intralaboratory interassay variance was 7.5% (range: 3.9–10.9%). The overall interassay interlaboratory variance was consistent among laboratories and averaged 11.4% (range: 8.5–12.5%). All laboratories yielded similar profiles and magnitudes of responses for replicate unknown samples; dose response profiles observed in each of the laboratories were indistinguishable. Considering the positive or negative results, interassay interlaboratory concordance of results exceeded 90%. Correlation of optical density values between and among all laboratories was strong ( r > 0.9, P < 0.001). Collectively, the results demonstrated that the macELISA for measuring allergen-specific canine IgE is reproducible, and documents that consistency of results can be achieved not only in an individual laboratory by differing operators but also among laboratories using the same monoclonal-based ELISA.

Food allergens inducing a lymphocyte-mediated immunological reaction in canine atopic-like dermatitis

Canine atopic-like dermatitis (ALD) is suspected to be associated with food allergies, particularly those mediated by lymphocytes. In this study, 54 cases were included as ALD dogs, based on the negative IgE test results. In the dogs, the percentage of activated cells in helper-T lymphocytes was measured by flow cytometry using cultured peripheral lymphocytes under food allergen stimulation. We observed that 49 of the 54 ALD dogs (90.7%) had positive lymphocyte reactions against one or more food allergens. The most common food allergen was soybean, showing positive results in 21 dogs (42.9%), while the allergen to cause the lowest number of reactions was catfish (only 5 dogs, 10.2%). These results may be useful in considering elimination diets for ALD dogs.

A blinded, randomized, placebo-controlled trial of the efficacy and safety of the Janus kinase inhibitor oclacitinib (Apoquel®) in client-owned dogs with atopic dermatitis

Background

Pruritus is the hallmark clinical sign of atopic dermatitis (AD) in dogs. Preliminary study results suggest that oclacitinib, a selective Janus kinase inhibitor, could reduce pruritus and associated inflammatory skin lesions in dogs with AD.

Hypothesis/Objectives

The objective was to evaluate efficacy and safety of oclacitinib (Apoquel^®) for the control of AD in a randomized, double‐blind, placebo‐controlled trial.

Animals

Clinicians at 18 specialty clinics enrolled client‐owned dogs (n = 299) with a history of chronic AD.

Methods

Dogs were randomized to receive either oclacitinib (0.4–0.6 mg/kg twice daily for 14 days and then once daily for up to 112 days) or an excipient‐matched placebo. Owners assessed visual analog scale (VAS) scores of pruritus on days 0, 1, 2, 7, 14, 28, 56, 84 and 112. Clinicians assessed Canine AD Extent and Severity Index (CADESI‐02) scores on days 0, 14, 28, 56, 84 and 112.

Results

On days 1, 2, 7, 14 and 28, oclacitinib‐treated dogs had a 29.5, 42.3, 61.5, 66.7 and 47.4% reduction from baseline in owner‐assessed pruritus scores, respectively, compared with a 6.5, 9.1, 6.5, 3.9 and 10.4% reduction in placebo‐treated dogs. On days 14 and 28, dermatologists recorded a 48.4% reduction in CADESI‐02 scores in oclacitinib‐treated dogs compared with a 1.7% reduction and a 3.6% increase in placebo‐treated dogs. After day 28, >86% of all placebo‐treated dogs had moved to an open‐label study, making between‐group comparisons biased. Differences were significant at all time points assessed (P < 0.0001).

Conclusions and clinical importance

Oclacitinib provided rapid, effective and safe control of AD, with substantial improvement in VAS and CADESI‐02 scores.

LD-aminopterin in the canine homologue of human atopic dermatitis: a randomized, controlled trial reveals dosing factors affecting optimal therapy

Background

Options are limited for patients with atopic dermatitis (AD) who do not respond to topical treatments. Antifolate therapy with systemic methotrexate improves the disease, but is associated with adverse effects. The investigational antifolate LD-aminopterin may offer improved safety. It is not known how antifolate dose and dosing frequency affect efficacy in AD, but a primary mechanism is thought to involve the antifolate-mediated accumulation of 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR). However, recent in vitro studies indicate that AICAR increases then decreases as a function of antifolate concentration. To address this issue and understand how dosing affects antifolate efficacy in AD, we examined the efficacy and safety of different oral doses and schedules of LD-aminopterin in the canine model of AD.

Methods and Findings

This was a multi-center, double-blind trial involving 75 subjects with canine AD randomized to receive up to 12 weeks of placebo, once-weekly (0.007, 0.014, 0.021 mg/kg) or twice-weekly (0.007 mg/kg) LD-aminopterin. The primary efficacy outcome was the Global Score (GS), a composite of validated measures of disease severity and itch. GS improved in all once-weekly cohorts, with 0.014 mg/kg being optimal and significant (43%, P<0.01). The majority of improvement was seen by 8 weeks. In contrast, GS in the twice-weekly cohort was similar to placebo and worse than all once-weekly cohorts. Adverse events were similar across all treated cohorts and placebo.

Conclusions

Once-weekly LD-aminopterin was safe and efficacious in canine AD. Twice-weekly dosing negated efficacy despite having the same daily and weekly dose as effective once-weekly regimens. Optimal dosing in this homologue of human AD correlated with the concentration-selective accumulation of AICAR in vitro, consistent with AICAR mediating LD-aminopterin efficacy in AD.

Gene expression in the skin of dogs sensitized to the house dust mite Dermatophagoides farinae

Atopic dermatitis is a multifactorial allergic skin disease in humans and dogs. Genetic predisposition, immunologic hyperreactivity, a defective skin barrier, and environmental factors play a role in its pathogenesis. The aim of this study was to analyze gene expression in the skin of dogs sensitized to house dust mite antigens. Skin biopsy samples were collected from six sensitized and six nonsensitized Beagle dogs before and 6 hr and 24 hr after challenge using skin patches with allergen or saline as a negative control. Transcriptome analysis was performed by the use of DNA microarrays and expression of selected genes was validated by quantitative real-time RT-PCR. Expression data were compared between groups (unpaired design). After 24 hr, 597 differentially expressed genes were detected, 361 with higher and 226 with lower mRNA concentrations in allergen-treated skin of sensitized dogs compared with their saline-treated skin and compared with the control specimens. Functional annotation clustering and pathway- and co-citation analysis showed that the genes with increased expression were involved in inflammation, wound healing, and immune response. In contrast, genes with decreased expression in sensitized dogs were associated with differentiation and barrier function of the skin. Because the sensitized dogs did not show differences in the untreated skin compared with controls, inflammation after allergen patch test probably led to a decrease in the expression of genes important for barrier formation. Our results further confirm the similar pathophysiology of human and canine atopic dermatitis and revealed genes previously not known to be involved in canine atopic dermatitis.

Food-specific serum IgE and IgG reactivity in dogs with and without skin disease: lack of correlation between laboratories

BACKGROUND

Despite conflicting data on their utility and no reports on interlaboratory reproducibility, serum food-specific antibodies are commonly assayed in first-opinion canine practice.

HYPOTHESIS/OBJECTIVES

To determine both the variability of test results between two laboratories and the frequencies and magnitudes of food reactivity in dogs of different disease status.

ANIMALS

Sera were obtained from eight dogs with cutaneous adverse food reaction (Group A), 22 with nonfood-induced atopic dermatitis (Group B), 30 with an allergic/inflammatory phenotype (Group C), 12 with miscellaneous skin diseases (Group D) and nine healthy dogs (Group E).

METHODS

Paired sera were submitted to two laboratories (A and B) for assays of food-specific IgE and IgG antibodies.

RESULTS

Numbers of positive IgE and IgG tests determined by each laboratory in Groups A, B, D and E were comparable (Group C not included). Significant differences in the magnitude of IgE reactivity between groups for each allergen were seen only for lamb (Laboratory A, P = 0.003); lamb reactivity in Group D exceeded Group E (P = 0.004) but was comparable between all other groups. Agreement (kappa statistic) between the two laboratories' tests was 'moderate' for one antigen (potato IgE), 'fair' for four (corn IgE, rice IgE and IgG and soya bean IgG), 'slight' for eight (six IgE and two IgG) and 'less than chance' for the remaining six antigens (three IgE and three IgG).

CONCLUSIONS AND CLINICAL IMPORTANCE

These laboratories' tests appear to have dubious predictive clinical utility because they neither correlate nor distinguish between dogs of different disease status.

Agreement between allergen-specific IgE assays and ensuing immunotherapy recommendations from four commercial laboratories in the USA

BACKGROUND

Canine allergen-specific IgE assays in the USA are not subjected to an independent laboratory reliability monitoring programme.

HYPOTHESIS/OBJECTIVES

The aim of this study was to evaluate the agreement of diagnostic results and treatment recommendations of four serum IgE assays commercially available in the USA.

METHODS

Replicate serum samples from 10 atopic dogs were submitted to each of four laboratories for allergen-specific IgE assays (ACTT(®) , VARL Liquid Gold, ALLERCEPT(®) and Greer(®) Aller-g-complete(®) ). The interlaboratory agreement of standard, regional panels and ensuing treatment recommendations were analysed with the kappa statistic (κ) to account for agreement that might occur merely by chance. Six comparisons of pairs of laboratories and overall agreement among laboratories were analysed for ungrouped allergens (as tested) and also with allergens grouped according to reported cross-reactivity and taxonomy.

RESULTS

The overall chance-corrected agreement of the positive/negative test results for ungrouped and grouped allergens was slight (κ = 0.14 and 0.13, respectively). Subset analysis of the laboratory pair with the highest level of diagnostic agreement (κ = 0.36) found slight agreement (κ = 0.13) for ungrouped plants and fungi, but substantial agreement (κ = 0.71) for ungrouped mites. The overall agreement of the treatment recommendations was slight (κ = 0.11). Altogether, 85.1% of ungrouped allergen treatment recommendations were unique to one laboratory or another.

CONCLUSIONS AND CLINICAL IMPORTANCE

Our study indicated that the choice of IgE assay may have a major influence on the positive/negative results and ensuing treatment recommendations.

Efficacy of dimetinden and hydroxyzine/chlorpheniramine in atopic dogs: a randomised, controlled, double-blinded trial

Antihistaminic drugs are commonly used as symptomatic therapy of atopic dermatitis in dogs. Unfortunately, their clinical benefit is largely unsubstantiated. In a double-blinded, placebo-controlled, cross-over trial, the influence of dimetinden and of a combination of chlorpheniramine and hydroxyzine on pruritus and lesions was evaluated in 19 dogs. They were treated with either product or a placebo orally for 14 days, each time followed by a 14-day washout period. Before and after each period, the dogs were examined and the Canine Atopic Dermatitis Extent and Severity Index (CADESI) determined by a clinician, and the pruritus and general condition by the owner. Dimetinden improved the pruritus significantly (P=0.014) but not the CADESI (P=0.087), the combination of hydroxyzine and chlorpheniramine improved the CADESI (P=0.049) and pruritus (P=0.05) significantly. Ten of 17 dogs improved by more than 25 per cent in pruritus with the combination of hydroxyzine and chlorpheniramine, 12 of 18 with dimetindenmaleate and only 2 of 19 with placebo. Antihistamines can help to reduce pruritus in atopic dogs, but in most cases, the improvement is limited and additional treatment may be needed.

Clinical use of a ceramide-based moisturizer for treating dogs with atopic dermatitis

In humans, skin barrier dysfunction is thought to be responsible for enhanced penetration of allergens. Similar to conditions seen in humans, canine atopic dermatitis (CAD) is characterized by derangement of corneocytes and disorganization of intercellular lipids in the stratum corenum (SC) with decreased ceramide levels. This study was designed to evaluate the effects of a moisturizer containing ceramide on dogs with CAD. Dogs (n = 20, 3~8 years old) with mild to moderate clinical signs were recruited and applied a moisturizer containing ceramide for 4 weeks. Transepidermal water loss (TEWL), skin hydration, pruritus index for canine atopic dermatitis (PICAD) scores, and canine atopic dermatitis extent and severity index (CADESI) scores of all dogs were evaluated. Skin samples from five dogs were also examined with transmission electron microscopy (TEM) using ruthenium tetroxide. TEWL, PICAD, and CADESI values decreased (p < 0.05) and skin hydration increased dramatically over time (p < 0.05). Electron micrographs showed that the skin barrier of all five dogs was partially restored (p < 0.05). In conclusion, these results demonstrated that moisturizer containing ceramide was effective for treating skin barrier dysfunction and CAD symptoms.

Genome-wide analysis in German shepherd dogs reveals association of a locus on CFA 27 with atopic dermatitis

Humans and dogs are both affected by the allergic skin disease atopic dermatitis (AD), caused by an interaction between genetic and environmental factors. The German shepherd dog (GSD) is a high-risk breed for canine AD (CAD). In this study, we used a Swedish cohort of GSDs as a model for human AD. Serum IgA levels are known to be lower in GSDs compared to other breeds. We detected significantly lower IgA levels in the CAD cases compared to controls (p = 1.1 × 10(-5)) in our study population. We also detected a separation within the GSD cohort, where dogs could be grouped into two different subpopulations. Disease prevalence differed significantly between the subpopulations contributing to population stratification (λ = 1.3), which was successfully corrected for using a mixed model approach. A genome-wide association analysis of CAD was performed (n cases = 91, n controls = 88). IgA levels were included in the model, due to the high correlation between CAD and low IgA levels. In addition, we detected a correlation between IgA levels and the age at the time of sampling (corr = 0.42, p = 3.0 × 10(-9)), thus age was included in the model. A genome-wide significant association was detected on chromosome 27 (praw = 3.1 × 10(-7), pgenome = 0.03). The total associated region was defined as a ~1.5-Mb-long haplotype including eight genes. Through targeted re-sequencing and additional genotyping of a subset of identified SNPs, we defined 11 smaller haplotype blocks within the associated region. Two blocks showed the strongest association to CAD. The ~209-kb region, defined by the two blocks, harbors only the PKP2 gene, encoding Plakophilin 2 expressed in the desmosomes and important for skin structure. Our results may yield further insight into the genetics behind both canine and human AD.

Ciclosporin therapy is associated with minimal changes in calcium metabolism in dogs with atopic dermatitis

BACKGROUND

Ciclosporin is widely used in the management of canine atopic dermatitis. In humans, ciclosporin therapy has been linked to disturbances in calcium metabolism and resultant skeletal disorders.

OBJECTIVES

The objective of this study was to assess calcium homeostasis in dogs before and after a 6 week course of once daily oral ciclosporin at the licensed dose (5 mg/kg).

ANIMALS

Sixteen client-owned dogs with spontaneous atopic dermatitis.

METHODS

Serum concentrations of calcium, phosphate, creatinine, 25-hydroxyvitamin D, 1,25-dihyroxyvitamin D and plasma concentrations of ionized calcium and parathyroid hormone (PTH) were measured, together with the urinary fractional excretion of calcium and phosphate. The extent of skin lesions was scored using the Canine Atopic Dermatitis Extent and Severity Index (CADESI)-03 and the degree of pruritus by the Edinburgh Pruritus Scale prior to and at the end of the study.

RESULTS

The CADESI-03 and the Edinburgh Pruritus Scale scores decreased satisfactorily in all dogs by the end of the study. Plasma PTH concentrations were significantly increased (P = 0.02) following ciclosporin treatment, whereas all other biochemical parameters were not significantly different from their starting values. The increase in PTH was mild in most cases and the proportion of dogs that had a PTH concentration above the reference range was not significantly different following treatment.

CONCLUSIONS AND CLINICAL IMPORTANCE

This study indicates that ciclosporin has minimal impact on calcium metabolism in dogs with atopic dermatitis when used at the licensed and clinically effective dosage for 6 weeks.

Development and validation of the Canine Atopic Dermatitis Lesion Index, a scale for the rapid scoring of lesion severity in canine atopic dermatitis

BACKGROUND

The third iteration of the Canine Atopic Dermatitis Extent and Severity Index (CADESI-03) is the only tool rigorously validated for canine atopic dermatitis (CAD) lesion scoring. The CADESI-03 requires 248 evaluations, limiting its widespread use.

HYPOTHESIS/OBJECTIVES

The goal of the study was to develop and validate a practical method of grading CAD lesions that requires scoring only the frequently affected body regions.

ANIMALS

Fifty-seven privately owned atopic dogs were used in the study.

METHODS

The Canine Atopic Dermatitis Lesion Index (CADLI) was evaluated in an open, multicentre reliability study. Validity was assessed with expert opinion (content validity) and comparison of CADLI with existing disease severity measures (construct and criterion validity). Reliability was evaluated by analysing repeated observations of each dog. Convenience was assessed in terms of the time required to complete the scale.

RESULTS

The CADLI scores correlated with overall assessment scores (r = 0.60, P < 0.001, linear mixed model) and pruritus severity scores (r = 0.53, P < 0.001, linear mixed model), establishing construct validity. The CADLI was strongly correlated with CADESI-03 (r = 0.84, P < 0.001, linear mixed model), establishing criterion validity. The CADLI values obtained by two observers correlated very strongly (r = 0.91, P < 0.001), as did the repeat values for the same observer (r = 0.98, P < 0.001). The mean time to complete the CADLI was less than that required for CADESI-03 (1.9 and 12.6 min, respectively), a highly significant difference (P < 0.001).

CONCLUSION AND CLINICAL IMPORTANCE

The CADLI was found to be an effective measure of CAD lesion severity, strongly correlating with CADESI-03. The convenience of CADLI makes it suitable for use in both clinical research and practice.

Dust mite species in the households of mite-sensitive dogs with atopic dermatitis

BACKGROUND

The presence of important house dust and storage mite species in the microenvironment of atopic dogs has not been thoroughly investigated.

OBJECTIVES

To compare the presence and population of five dust mite species (Dermatophagoides farinae, Dermatophagoides pteronyssinus, Acarus siro, Tyrophagus putrescentiae and Lepidoglyphus destructor) among households with mite-sensitive atopic dogs (Group A), households with clinically healthy dogs (Group B) and households without pets (Group C, n=25) in Greece.

ANIMALS

Twenty mite-sensitive atopic dogs and 20 clinically healthy dogs.

METHODS

Dust samples were collected with a vacuum cleaner from owners' mattresses (all groups) and from dogs' sleeping areas (Groups A and B) or living room couch (Group C), once every season of the year. Following dust flotation, mites were counted and identified.

RESULTS

Dermatophagoides farinae was the most prevalent (60, 40 and 64% in Groups A, B and C, respectively), followed by D. pteronyssinus (45, 35 and 48%, respectively), whereas the three storage mites were found in fewer households. No major differences could be found between Groups A and B or between households with (Groups A and B) and without dogs (Group C) regarding the presence or numbers of the five dust mite species.

CONCLUSIONS AND CLINICAL IMPORTANCE

The presence and population of five common house dust and storage mite species does not differ among Greek households with mite-sensitive atopic dogs, households with healthy dogs and households without pets.

Two loci on chromosome 5 are associated with serum IgE levels in Labrador retrievers

Crosslinking of immunoglobulin E antibodies (IgE) bound at the surface of mast cells and subsequent mediator release is considered the most important trigger for allergic reactions. Therefore, the genetic control of IgE levels is studied in the context of allergic diseases, such as asthma, atopic rhinitis, or atopic dermatitis (AD). We performed genome-wide association studies in 161 Labrador Retrievers with regard to total and allergen-specific immunoglobulin E (IgE) levels. We identified a genome-wide significant association on CFA 5 with the antigen-specific IgE responsiveness to Acarus siro. We detected a second genome-wide significant association with respect to the antigen-specific IgE responsiveness to Tyrophagus putrescentiae at a different locus on chromosome 5. A. siro and T. putrescentiae both belong to the family Acaridae and represent so-called storage or forage mites. These forage mites are discussed as major allergen sources in canine AD. No obvious candidate gene for the regulation of IgE levels is located under the two association signals. Therefore our studies offer a chance of identifying a novel mechanism controlling the host's IgE response.