The influence of topical unsaturated fatty acids and essential oils on normal and atopic dogs

Seven dogs with atopic dermatitis and six normal dogs were treated with a spot-on product containing essential oils and unsaturated fatty acids q 7 days for 8 wk. Seven additional atopic dogs received a daily spray containing similar ingredients to the spot-on. In all dogs, transepidermal water loss (TEWL) was measured before and after treatment using a closed chamber device. In atopic dogs, a validated lesion score (canine atopic dermatitis extent and severity index, CADESI) was determined and pruritus was assessed with a visual analog scale before and after treatment. The mean CADESI scores in atopic dogs decreased with the spot-on (P=0.0043) and with the spray (P=0.0366). Similarly, the pruritus scores decreased with the spot-on (P=0.266) and with the spray (P=0.0177). There was a significant difference between the TEWL values of healthy and atopic dogs on the abdomen (P=0.0181) and back (P=0.0123). TEWL decreased significantly on the back after treatment with the spray (P=0.016), but not on the abdomen (P=0.078). Adverse effects were not observed. The results of this pilot study indicate that topical fatty acids and essential oils are a useful treatment option for canine atopic dermatitis.     

FC-38 Efficacy of conjugated linoleic acid and black currant seed oil in the treatment of canine atopic dermatitis: a double-blinded, randomized, placebo-controlled study

The purpose of this study was to evaluate a combination of immunostimulatory bacterial DNA sequences and allergen-specific immunotherapy for the treatment of canine atopic dermatitis. Seven dogs with nonseasonal atopic dermatitis diagnosed by history, clinical signs and exclusion of differential diagnoses were included. All dogs had been on allergen-specific immunotherapy for at least 12 months with incomplete responses, were on additional antipruritic therapy and showed residual pruritus. Pruritus was marked by the owner on a visual analogue scale, lesions were determined by a clinician using the Canine Atopic Dermatitis Extent and Severity Index (CADESI), and concurrent medications were recorded before entering the study and after 14 weeks of treatment. Peripheral blood mononuclear cells were isolated and cultured; canine cytokine message for IFNγ, IL-4, TNF and IL-10 was quantitated using RT-PCR. A mixture of allergen extract and liposome-DNA complexes was injected intradermally at the beginning of the study and after 2, 4, 6, 10 and 14 weeks. CADESI, pruritus and medication scores, and cytokine messages at the beginning and end of the study were compared with a paired t -test. There were significant improvements in pruritus scores ( P  = 0.0277). Reductions in medication scores and CADESI were not statistically significant. IL-4 production decreased significantly ( P  = 0.0428); decreases in other cytokines were not significant. Although the number of dogs in this pilot study was small, the results warrant further investigation of a combination of immunostimulatory bacterial DNA sequences and allergen-specific immunotherapy for the treatment of canine atopic dermatitis.
Funding: Self-funded.     

Efficacy of an essential fatty acid-enriched diet in managing canine atopic dermatitis: a randomized, single-blinded, cross-over study

Evidence suggests that high-quality diets enriched with essential fatty acids (EFA) and other nutrients can ameliorate canine atopic dermatitis (AD). This study compared such a diet (Eukanuba Veterinary Diets Dermatosis FP) with a home-cooked equivalent (fish and potato) in a randomised, single-blinded, cross-over trial. Twenty dogs with perennial AD were randomly assigned to receive either the test (group A) or the control diet (group B) for 1 month, followed by the contrasting diet for a further month. Canine Atopic Dermatitis Extent and Severity Index (CADESI version 2) and pruritus (visual analogue scale) scores were recorded at days 0, 30 and 60. Eight dogs in each group completed the study. CADESI scores significantly declined when dogs were fed the test diet (group A P < 0.01; group B P < 0.001), and increased (group A P < 0.05) or remained steady (group B) on the control diet. CADESI scores decreased in 15 of 16 dogs fed the test diet, but this was less than 50% in all cases. Pruritus scores also declined when dogs were fed the test diet compared to the control diet, but this was only significant for group A (P = 0.027). Pruritus was reduced in 11 of 16 dogs fed the test diet, but this was 50% or more in only two dogs. This trial provides evidence for the efficacy of Eukanuba Veterinary Diets Dermatosis FP in canine AD, although it is likely that most cases will require adjunct therapy. The mechanism is unclear, but may involve increased and balanced EFA levels.     

FC‐36 The use of immunostimulatory bacterial DNA sequences in allergen‐specific immunotherapy of canine atopic dermatitis

The purpose of this study was to evaluate a combination of immunostimulatory bacterial DNA sequences and allergen‐specific immunotherapy for the treatment of canine atopic dermatitis. Seven dogs with nonseasonal atopic dermatitis diagnosed by history, clinical signs and exclusion of differential diagnoses were included. All dogs had been on allergen‐specific immunotherapy for at least 12 months with incomplete responses, were on additional antipruritic therapy and showed residual pruritus. Pruritus was marked by the owner on a visual analogue scale, lesions were determined by a clinician using the Canine Atopic Dermatitis Extent and Severity Index (CADESI), and concurrent medications were recorded before entering the study and after 14 weeks of treatment. Peripheral blood mononuclear cells were isolated and cultured; canine cytokine message for IFNγ, IL‐4, TNF and IL‐10 was quantitated using RT‐PCR. A mixture of allergen extract and liposome‐DNA complexes was injected intradermally at the beginning of the study and after 2, 4, 6, 10 and 14 weeks. CADESI, pruritus and medication scores, and cytokine messages at the beginning and end of the study were compared with a paired t‐test. There were significant improvements in pruritus scores (P = 0.0277). Reductions in medication scores and CADESI were not statistically significant. IL‐4 production decreased significantly (P = 0.0428); decreases in other cytokines were not significant. Although the number of dogs in this pilot study was small, the results warrant further investigation of a combination of immunostimulatory bacterial DNA sequences and allergen‐specific immunotherapy for the treatment of canine atopic dermatitis. Funding: Self‐funded.     

The effect of nematode administration on canine atopic dermatitis

Canine atopic dermatitis is a common disease and is considered as an animal model of the human disease. Immunomodulation by helminths is reported in several species. The aim of this study was to determine whether nematodes have an immunomodulatory effect on atopic dermatitis in dogs. In the pilot study, 12 atopic dogs were infected with either embryonated eggs of Trichuris vulpis (500 and 2500 eggs in 3 dogs each) or L3 larvae of Uncinaria stenocephala (100, 500 and 2500 eggs in 2 dogs each), respectively, for 3 months. Pruritus was evaluated with visual analogue scales and clinical lesions with the canine atopic dermatitis extent and severity index (CADESI). Skin biopsies were obtained for histopathology at the beginning and end of the study. In the subsequent placebo-controlled, double-blinded, randomised study, 21 dogs received either 2500 embryonated T. vulpis eggs or placebo and were evaluated similarly. In addition, allergen-specific serum IgE concentrations were determined. All dogs in the pilot study improved in their lesion scores, most in their pruritus scores. The cutaneous inflammatory infiltrate did not change significantly. In the subsequent randomised study, there was no significant difference between placebo and Trichuris administration in regard to pruritus or CADESI. IgE concentrations also did not change significantly. Infection with T. vulpis did not significantly change clinical signs of canine atopic dermatitis.     

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.     

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.     

The efficacy of cyclosporine A in cats with presumed atopic dermatitis: a double blind, randomised prednisolone-controlled study

The objective of this study was to compare the efficacy of cyclosporine A (CsA) and prednisolone in feline atopic dermatitis (AD) in a randomised, controlled double blind study. Twenty-nine cats with feline AD were randomly allocated to two groups. Eleven cats were treated orally with prednisolone (1mg/kg SID) and 18 were treated with CsA (5mg/kg/day) for 4 weeks. At day 0 (D0) and D28, skin lesions were graded by means of the canine atopic dermatitis extent and severity index (CADESI). Skin biopsies and intradermal allergy tests were performed at D0 and blood samples for haematology and serum biochemistry were collected at D0 and D28. During the trial the cat owners were asked to evaluate the intensity of the pruritus once weekly on a linear analog scale and to record side effects. Based on the CADESI there was no significant difference between the two groups in the amount of remission (P=0.0562) or in the number of cats that improved by >25% (P=0.0571). The effect of CsA and prednisolone on pruritus as evaluated by the owners was not significantly different (P=0.41) between the two groups. No serious side effects were observed. The conclusion was that CsA is an effective alternative to prednisolone therapy in cats with presumed atopic dermatitis.     

Clinical trial evaluating the efficacy and safety of cyclosporine in dogs with atopic dermatitis

OBJECTIVE: To determine efficacy and safety of cyclosporine in the treatment of atopic dermatitis among dogs in North America. DESIGN: Randomized controlled (phase 1) and open-label (phase 2) trials. ANIMALS: 268 dogs with atopic dermatitis. PROCEDURE: In phase 1, dogs were randomly assigned to be treated with cyclosporine (5 mg/kg [2.3 mg/Ib], PO, q 24 h) or a placebo. In phase 2, all dogs were treated with cyclosporine for 16 weeks. Frequency of cyclosporine administration was decreased if dogs improved clinically. RESULTS: At the end of phase 1, canine atopic dermatitis extent and severity index (CADESI) scores for dogs treated with cyclosporine were significantly lower than scores for control dogs. Percentage of dogs with severe pruritus decreased from 67% to 16% for the cyclosporine group but from 66% to only 61% for the control group. During phase 2, cyclosporine dosage was decreased to every-other-day administration in 39% of the dogs after 4 weeks. After 12 weeks, 22% of the dogs were treated twice weekly and 36% were treated every other day. After 16 weeks, CADESI score had decreased > 50% in 68% of the dogs and 47% of dogs had no or mild pruritus. The most frequent adverse reactions were gastrointestinal tract signs. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that cyclosporine is efficacious for the treatment of atopic dermatitis in dogs and that frequency of cyclosporine administration can be reduced following an initial induction period. The drug was well tolerated.     

Efficacy of a 0.0584% hydrocortisone aceponate spray in the management of canine atopic dermatitis: a randomised, double blind, placebo-controlled trial

This study evaluated a 0.0584% hydrocortisone aceponate (HCA) spray (Cortavance®; Virbac SA, Carros, France) in canine atopic dermatitis (AD). Initially, dogs with a canine AD extent and severity index (CADESI-03) ≥ 50 were randomly allocated to receive HCA ( n  = 15) or placebo ( n  = 13) (two sprays from 10 cm away to treat an area of 100 cm²) once daily for 28 days. Twenty-one of the dogs then received HCA spray once daily, reducing to every other day or twice weekly over 42 days if improvement was maintained. CADESI, pruritus (14 cm visual-analogue-scale) and owner satisfaction (5-point scale) were recorded every 14 days. Haematology, biochemistry and adrenocorticotrophic hormone stimulation were performed at baseline, d28 and d70 (HCA n  = 9; placebo n  = 7). Intention-to-treat data were analysed. HCA spray significantly decreased CADESI (–61.4% versus –13.4%, P  = 0.0069) and pruritus (–38.8% versus +57.6%, P  = 0.0015) at d28 compared to placebo. Scores were significantly decreased at d14 (CADESI –50.5%, P  < 0.0021) and d28 (CADESI P  < 0.0001; pruritus P  = 0.018) compared to baseline following HCA but not placebo. At d28 11 of 15 and 7 of 15 HCA dogs had ≥ 50% reductions in CADESI and pruritus compared to 3 of 13 ( P  = 0.02) and 1 of 13 ( P  = 0.04) placebo dogs. Owner satisfaction scores were significantly higher in the HCA group (d28 P  = 0.0001). Daily 3 of the 21 dogs required daily maintenance therapy, 7 every other day, 6 twice weekly and 5 dogs required additional therapy. Coat length did not influence the results. No adverse effects or changes to blood parameters were noted. HCA spray proved safe and effective up to 70 days. It is not, however, licensed for long-term treatment.     

A randomized, controlled study to evaluate the steroid sparing effect of essential fatty acid supplementation in the treatment of canine atopic dermatitis

A randomized, double blind, placebo-controlled multicentre clinical trial of 12 weeks' duration was undertaken in 60 dogs with atopic dermatitis to evaluate the steroid sparing effect of essential fatty acid supplementation. The dogs were randomly assigned to receive either a combination of borage seed oil and fish oil or a placebo, in addition to prednisolone tablets. All dogs received a standardized basal diet. Owners of the dogs recorded pruritus daily using a 10 cm visual analog scale and the dosage of prednisolone was established based on the pruritus score, according to written instructions. The dosage of prednisolone and the use of any concurrent treatment (shampoo and/or ear-cleanser) were recorded by the owner on a daily basis. The investigators graded the skin lesions at days 0, 42 and 84. The use of prednisolone during the test period was lower in the active group, but the difference was not statistically significant (P = 0.32). The test period was sequentially divided into 43-84, 50-84, 57-84, 64-84, 71-84 and 78-84 days. On day 64, the difference between the active group and the placebo group reached statistical significance (P = 0.04) with an increasing difference towards the end of the study. A statistically significant reduction in the pruritus scores and the total clinical scores from day 0 to day 84 was apparent in both groups (P < 0.0001). At the end of the study, both the pruritus score and the total clinical score were lower in the active group. Our findings indicate a steroid sparing effect of essential fatty acid supplementation in canine atopic dermatitis and, furthermore, that there is a time lag before the effect is attained.     

Efficacy of cyclosporin in the treatment of atopic dermatitis in dogs--combined results from two veterinary dermatology referral centres

OBJECTIVE: To evaluate the efficacy of cyclosporin in controlling the clinical signs associated with atopic dermatitis in dogs under Australian field conditions. DESIGN: A multicentre prospective clinical investigation of the use of cyclosporin in 41 dogs with atopic dermatitis. PROCEDURE: Dogs were treated with cyclosporin (5 mg/kg orally once daily with food) for 6 weeks. Four clinical parameters of severity of atopic dermatitis were measured on Day 0 and on Day 42 using a 0 to 4 scoring system. Individual variables were then combined to form a Global Score. Both client and clinician observed pruritus scores were combined to form a Pruritus Score. Pre- and post-treatment scores were statistically analysed. The difference in results between the two investigators was also recorded and analysed. RESULTS: All dogs showed a marked reduction in pruritus and erythema during the 6-week treatment period. All dogs showed a significant (P < 0.001) improvement in clinical lesion scores and Global Score (P < 0.001). The mean percentage improvement in Global Score from Day 0 to Day 42 was 83.9%. The mean percentage improvement in Pruritus Score from Day 0 to Day 42 was 83%. The medication was well tolerated. Side effects such as vomiting, diarrhoea and soft stools were observed in four dogs. Another four dogs developed bacterial pyoderma during the trial period. There was no significant difference in results between the two centres. CONCLUSION: Cyclosporin was well tolerated and efficacious in the symptomatic treatment of atopic dermatitis in dogs attending two veterinary dermatology referral centres in Australia, under Australian field conditions, when administered at 5 mg/kg/day for 6 weeks.     

Are transepidermal water loss and clinical signs correlated in canine atopic dermatitis? A compilation of studies

Background – Cutaneous impairment plays a crucial role in atopic dermatitis (AD). Transepidermal water loss (TEWL) measurement is an indirect assessment of skin barrier function and correlates with disease severity in humans. Skin impairment also exists in canine AD; however, concerns exist regarding variability and reliability of TEWL measurements in dogs. Hypothesis/Objectives – The purposes of this retrospective study were twofold: first, to investigate the correlation between severity of dermatitis [measured by Canine Atopic Dermatitis Extent and Severity Index (CADESI)] and TEWL; and second, to evaluate whether increased TEWL at a young age correlates with disease severity later in life. Methods – Data from atopic beagles and dogs with natural AD were analysed. Transepidermal water loss was measured in atopic beagles (n = 24) with an open chamber and in dogs with naturally occurring AD with a closed chamber device (two studies, with n = 14 and n = 18). Pearson product–moment correlation was used for analyses. Transepidermal water loss of the inguinal region, axilla, antebrachial flexure and pinna was analysed. Correlations were investigated for each study, separately first and then jointly. They included CADESI and TEWL of individual regions, total CADESI and total TEWL of all measured regions, and total CADESI and TEWL of key regions. Results – In atopic beagles, TEWL measured at 1 year of age pre‐ and post‐allergen challenge was correlated with CADESI at 1, 3 and 6 years of age. Overall, low correlation coefficients were found; therefore, a biologically relevant connection could not be demonstrated. The main significant positive correlation was found between TEWL in the pinna and total CADESI. Conclusions and clinical importance – It is concluded that TEWL does not correlate with disease severity.     

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.     

Late-phase reactions to intradermal testing with Dermatophagoides farinae in healthy dogs and dogs with house dust mite-induced atopic dermatitis

OBJECTIVE: To determine the prevalence of late-phase reactions to intradermal testing with Dermatophagoides farinae in healthy dogs and dogs with atopic dermatitis and an immediate reaction to D farinae. ANIMALS: 6 healthy dogs and 20 dogs with atopic dermatitis and immediate reactions to D farinae. PROCEDURE: ntradermal tests were performed with D farinae at 1:1,000 wt/vol and 1:50,000 wt/vol concentrations, and skin reactivity was evaluated after 0.25, 6, and 24 hours. Serum D farinae-specific IgE antibodies were assayed. Extent of lesions (atopy index) and pruritus (visual analogue scale) were evaluated in dogs with atopic dermatitis. RESULTS: Late-phase reactions were observed in healthy dogs at 6 hours (n = 2 dogs) and 24 hours (1) with the 1:1,000 wt/vol concentration, and at 6 hours (1) and 24 hours (1) with the 1:50,000 wt/vol concentration of allergen. Late-phase reactions in healthy dogs were only observed in dogs with an immediate reaction to D farinae. Late-phase reactions were observed in 11 of 20 dogs with atopic dermatitis at 6 and 24 hours with the 1:1,000 wt/vol concentration and in 10 of 20 at 6 and 24 hours with the 1:50,000 wt/vol concentration of allergen. There was no difference in mean atopy index, mean visual analogue scale of pruritus, or mean serum D farinae-specific IgE concentration of dogs with a late-phase reaction, compared to dogs without a late-phase reaction. CONCLUSIONS AND CLINICAL RELEVANCE: Late-phase reactions may be observed after an immediate reaction to intradermal skin testing in healthy and allergic dogs but are more commonly observed in dogs with atopic dermatitis.     

Malassezia dermatitis in dogs in Brazil: diagnosis,evaluation of clinical signs and molecular identification

Skin carriage and quantification of Malassezia yeasts were evaluated in 180 healthy dogs (group 1) and 117 dogs with clinical signs (pruritus, erythema, lichenification/seborrhoea, excoriations and alopecia) that could be related to Malassezia dermatitis (group 2) in Brazil. The lesions in the group 2 dogs were evaluated using CADESI‐03 scores. Samples were collected from five different anatomical areas. Direct examination was performed using the tape strip technique, and results were expressed as the mean number of yeasts per ×1000 microscopic field per dog. For mycological culture, a single piece of sterilized carpet was applied to the same areas sampled for cytology, and transferred onto Dixon’s modified medium. Yeast populations were expressed as mean colony forming units (CFU)/plate. Malassezia isolates were characterized by polymerase chain reaction–restriction endonuclease analysis of the large subunit (LSU) of ribosomal RNA gene. The probability of culturing Malassezia from dogs with skin lesions was significantly higher (P < 0.001) than from healthy dogs. There was a linear trend between CADESI‐03 score and mean CFU/plate. Group 2 dogs with positive cultures had higher CADESI‐03 scores than those with negative cultures (P < 0.05). Almost all isolates were identified as Malassezia pachydermatis. Only one isolate (group 2) was identified as Malassezia furfur. These data suggest that dogs with skin disorders harbouring Malassezia yeasts in quantities higher than 120 mean CFU/plate should be considered as having Malassezia dermatitis. The presence of Malassezia appears to exacerbate clinical lesions in dogs.     

Intradermal injection of heat-killed Mycobacterium vaccae in dogs with atopic dermatitis: a multicentre pilot study

Canine atopic dermatitis (cAD) is a common disease with a multifactorial aetiology associated with impaired immunoregulation. The immunopathogenesis has similarities to that of human atopic dermatitis. Clinical signs of allergic disease in humans and mice are reduced by administration of saprophytic mycobacteria that amplify regulatory cytokines and hence the effect of Mycobacterium vaccae on the clinical severity of cAD was investigated. Sixty-two dogs with cAD, selected according to strict criteria, were treated with a single intradermal injection and evaluated monthly for 3 months in a placebo-controlled double-blind clinical trial. Clinical severity was quantified using standardized scores and by owner assessment of pruritus. A single injection of a heat-killed suspension of M. vaccae was found to be well tolerated and effective in treating mild to moderate cases of cAD demonstrable for 3 months, but was insignificant in more severely affected dogs.