P‐26 New aspects of canine demodicosis and the possibility of treatment with selamectin

The purpose of this study was to evaluate 55 clinical cases of canine demodicosis and to compare the results of treatment using amitraz (solution), selamectin (spot‐on), ivermectin (injection) and cythioate (oral tablets). Data from the 55 cases was collected and evaluated after clinical and microbiological examination. Treatment was selected depending on the severity of demodicosis and compliance of the owner. The cases were followed for 12 months and the status of the patients was grouped on two levels: recovered (58%), or relapsed (42%). Five dogs (9%) were euthanized. The disease was commonly diagnosed in purebred dogs. Demodicosis was more common in dogs under 2 years of age (65%), in males (64%), and in the short‐haired breeds (75%). Demodicosis was generalized in 73% of cases, localised in 23% and affected the feet (pododemodicosis) in 4% of cases. Recovery was the highest in dogs between 1 and 2 years of age (73%), and in the localized cases (92%). Nonspecific treatment with glucocorticoids prior to the diagnosis lowered the rate of recovery (4%), but treatment with glucocorticoids for proven atopic dermatitis improved the rate of recovery (41%). All drugs (amitraz, selamectin, cythioate) administered for the localized form were effective (100% recovered). Recovery in generalized demodicosis was 60% using ivermectin, 55% using amitraz, 44% with the combination of amitraz and selamectin (two treatments with amitraz followed by selamectin), and 43% in cases where selamectin was used alone. Funding: Pfizer Animal Health.     

Efficacy and safety of topical administration of selamectin for treatment of ear mite infestation in rabbits

OBJECTIVE: To evaluate the efficacy and safety of topical administration of selamectin in rabbits naturally infested with Psoroptes cuniculi. DESIGN: Randomized controlled trial. ANIMALS: 48 mixed-breed domestic rabbits with active P. cuniculi mite populations and clinical ear lesions. PROCEDURES: Rabbits were randomly allocated to 1 of 6 treatment groups. On day 0, rabbits in groups 1 and 2 were given vehicle, rabbits in groups 3 and 4 were given selamectin at a dose of 6 mg/kg (2.7 mg/lb), and rabbits in groups 5 and 6 were given selamectin at a dose of 18 mg/kg (8.2 mg/lb). On day 28, rabbits in groups 2, 4, and 6 were given a second dose of vehicle or selamectin. Otoscopic examinations were performed and ear lesion size was measured weekly for 8 weeks. Quantitative viable mite counts were performed on day 56. RESULTS: On days 7 through 56, lesion sizes for all selamectin-treated groups were significantly lower than sizes for control groups; there were no significant differences in lesion sizes among selamectin-treated groups. All rabbits in the 2 control groups had viable adult P. cuniculi mites for the duration of the study, as determined by otoscopic examination, whereas all rabbits in the 4 selamectin-treated groups were free from P. cuniculi mites on days 7 through 56. No adverse reactions associated with selamectin treatment were observed. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that topical application of selamectin at a dose of 6 or 18 mg/kg can completely eliminate mites from rabbits naturally infested with P. cuniculi.     

P‐5 Importance of psychogenic factors in canine recurrent pyoderma

Recurrent pyoderma is a relapsing bacterial infection of the skin. Evaluation of the primary predisposing factors is essential, but they are not always easy to determine. We reported that psychogenic factors should be considered as one cause of canine dermatoses featuring pruritic behavior such as grooming and scratching, and predicted that it could be added as a cause of recurrent pyoderma. The purpose of this study was to evaluate the roles of psychogenic factors in canine recurrent pyoderma. This study examined 21 dogs with recurrent pyoderma, which showed relapsing but antibiotic‐responsive skin lesions. Predisposing factors, especially allergy, infection, endocrine disorders, congenital factors and improper treatments, were carefully ruled out with standard diagnostic procedures. Diagnosis of psychogenic factors was based on fulfillment of the following features: (1) distinctive area of broken hairs or asymmetric erythema, (2) incidental pruritic behavior related to emotionally unstable situation or physiological intervention, (3) existence of environmental antecedent triggers or concurrent psychiatric symptoms, and (4) requirement for psychogenic treatment, consisting of behavior modification and psychopharmacological therapy in some. The incidence of psychogenic factors and the efficacy of the treatment in recurrent pyoderma were evaluated. In these 21 dogs, 10 cases (47.6%) were compatible with the presence of psychogenic factors, and seven cases (33.3%) were improved with behavioral treatment. Psychogenic factors should be considered in the aetiology of so‐called idiopathic canine recurrent pyoderma. Further investigation is needed to understand the relationship between skin barrier dysfunction and psychogenic factors. Funding: Self‐funded.     

P‐43 IgG antibodies against sarcoptic mite antigens in dogs cross‐reacting with house dust and storage mite antigens

Sera from dogs suffering from scabies were used to evaluate possible antigenic cross‐reactivity with proteins from house dust or storage mites. Polyacrylamide gel electrophoresis on gradient gels was used to create size‐dependent protein bands of Sarcoptes scabiei ssp. vulpis, Dermatophagoides farinae, D. pteronyssinus, Acarus siro, Lepidoglyphus destructor and Tyrophagus putrescentiae. Anti‐canine IgG antibodies conjugated with alkaline phosphatase were used for immunostaining. Different patterns for Sarcoptes could be seen with strong bands repetitively observed of approximately 22, 112, 116, 132 and 200 kD in size. The band at approximately 22 kD seems likely to have cross‐reactivity with a protein of the same size in A. siro. The one at approximately 200 kD might share antigenic activity with bands of D. farinae and, to a lesser extent, D. pteronyssinus. Funding: Laupeneck AG.     

Use of selamectin for the treatment of psoroptic and sarcoptic mite infestation in rabbits

Selamectin, a novel avermectin compound, was evaluated for its efficacy against naturally occurring infestations of Psoroptes cuniculi and Sarcoptes scabiei. A total of 42 New Zealand rabbits with psoroptic mange and 37 Angora rabbits with sarcoptic mange were used in the present study. On day 0, infested rabbits were treated topically with either selamectin at minimum dose of 6 mg kg(-1) (6-18 mg kg(-1) for New Zealand rabbits, n = 31 and 10-12 mg kg(-1) for Angora rabbits, n = 23) or vehicle only (control groups, n = 11 for New Zealand rabbits, n = 14 for Angora rabbits). The efficacy of selamectin was assessed both clinically and parasitologically by the presence or absence of viable mites. Rabbits were scraped for sarcoptic mites on days 7, 14, 28, 42 and 56 and had otoscopeic and/or microscopic examination for the detection of Psoroptes mites on days 7, 14, 42 and 56. Fisher's exact test was used to assess differences between the vehicle and selamectin treatment in the number of rabbits without mites (cure rates) on each assessment date. It was found that significantly fewer selamectin-treated rabbits had mites detected on skin scrapings (for S. scabiei) or otoscopeic and/or microscopic examination (for P. cuniculi) (P < 0.01) than the vehicle group. Results of the present study suggest that selamectin is effective against naturally infestations of P. cuniculi and S. scabiei in rabbits.     

P‐7 Treatment of canine acne with doxycycline: an open trial

The purpose of this study was to determine whether doxycycline (Ronaxan) decreased the severity of localized lesions of canine acne. Dogs were enrolled if they exhibited skin lesions localized to the chin compatible with canine acne, and if cytological smears showed a bacterial invasion and bacteriological samples grew Staphylococcus intermedius colonies. Demodicosis and dermatophytosis were excluded by skin scrapings and fungal culture, respectively. Lesions (erythema, lichenification, papules, pustules and excoriations) were graded with a quantitative 4‐point scale (maximal total score 15). Extent of lesion was also estimated. Pruritus was graded on a 4‐point scale. Scores were given at the time of inclusion and at day 30 after treatment with doxycycline 10 mg/kg once daily. Twelve dogs (10 males and two females) representing seven breeds were included. Good improvement of both lesional (9.4 before treatment and 2.3 after treatment) and extent scores (43% before treatment and 8% after treatment) was achieved. Pruritus was also markedly improved from 2.08 before treatment to 0.42 after treatment. One dog was not significantly improved after 1 month. Results of this trial suggest that doxycyline is useful for reducing the severity of localized skin lesions of canine acne. Funding: Self‐funded.     

Characterization of house dust mite and scabies mite allergens by use of canine serum antibodies

OBJECTIVE: To identify the major allergenic proteins from the 3 main species of dust mites to which dogs react (Dermatophagoides farinae, D. pteronyssinus, and Euroglyphus maynei) and evaluate the potential cross-reactivity of dust mite allergens with antigens from the ectoparasitic mite Sarcoptes scabiei var canis. SAMPLE POPULATION: Sera from 83 dogs with atopic dermatitis. PROCEDURE: Sodium dodecylsulfate-polyacrylamide gel electrophoresis and immunoblotting using serum from atopic dogs was used to identify IgE-binding proteins in extracts of the 4 mite species. RESULTS: Sera of atopic dogs contained IgE against 23, 17, 25, and 17 allergens from D. farinae, D. pteronyssinus, E. maynei, and S. scabiei, respectively. Unlike the situation for humans, the major allergens for dogs are mostly proteins that are larger than 90 kd molecular weight. Dermatophagoides farinae and E. maynei appear to be more allergenic for dogs than is D. pteronyssinus. Some dogs with serum IgE against dust mites also had IgE against antigens of S. scabiei var canis. CONCLUSIONS AND CLINICAL RELEVANCE: Multiple dust mite allergens induce an IgE response in dogs. These allergens are mostly greater than 90 kd molecular weight.     

P‐33 Poxvirus infection in two cats

A 3‐year‐old Burmese cat was presented with a history of nonresolving crusted and papular lesions of the face and prior treatment with prednisolone. Skin biopsies revealed typical pox lesions with hyperplasia and ulceration of the epidermis and eosinophilic cytoplasmic inclusion bodies in the epidermal cells. In the upper dermis there was prominent diffuse mast cell infiltration and mild neutrophilic and eosinophilic inflammation. Rare cytoplasmic inclusion bodies were also present in swollen endothelial cells of dermal venules, which showed no other degenerative changes. Histological diagnosis was confirmed by electron microscopic evidence of pox virus particles in inclusion bodies of epidermal cells. The lesions resolved within 6 weeks with systemic antibiotic therapy and supportive care. A 2‐year‐old domestic short‐haired cat was presented with multiple disseminated papular and ulcerative pox lesions with central eschar over the entire body. Histologically, large epidermal inclusion bodies (up to 6 μm in diameter) were present. Widespread haemorrhage and vascular wall necrosis was visible in the dermis and subcutis. Some subcutaneous vessels showed neutrophilic vasculitis. In addition to diffuse dermal neutrophilic and eosinophilic inflammation, a lymphohistiocytic panniculitis was also present. The cat died as a result of massive haemorrhage and lymphedema, despite supportive care. Funding: Self‐funded.     

P‐84 Experimental study of orange phototoxicity in sheep

We have evaluated the possible phototoxicity of an orange‐based diet on sheep in a controlled environment. The phototoxic effect of psoralens, potent phototoxic furocoumarins, contained in oranges could be manifested either as a perioral contact phototoxicity or as a postingestion phototoxic effect. This research has especial relevance in the region of Valencia, Spain, where sheep are occasionally fed large quantities of these agricultural by‐products and where sunlight is constant year‐round. Ewes were randomly allocated to two groups, one to be fed a maintenance diet (n = 9), and the other to receive, after a brief adaptation period, solely oranges (n = 6). The ewes were placed in an external enclosure and fed this diet for 2 months. At approximately 3‐week intervals, the ewes were subjected to thorough clinical and dermatological examination. Skin biopsies were obtained on two different occasions. All procedures were carried out under the guidelines of the local ethics committee. The sheep on the orange diet showed weight loss and a debilitated condition. However, during the study, no clinical or pathological signs of oral or systemic photodermatitis were observed. Funding: Self‐funded.     

P‐53 Histopathologic evaluation of feline plasmacytic pododermatitis

The purpose of this study was to evaluate the histopathologic changes seen in feline plasmacytic pododermatitis in an attempt to correlate clinical response with any specific histopathologic feature, and to evaluate these specimens for possible infectious organisms. Fourteen skin biopsies from cats with plasmacytic pododermatitis and a clinical follow‐up of 12–36 months were included in the study. Sections were stained with H&E as well as with a polyclonal anti‐Mycobacterium bovis [Bacille Calmette–Guerin (BCG)] antibody cross‐reactive to a broad spectrum of fungi and bacteria. Sections stained with the anti‐BCG antibody were graded as positive or negative. Inflammatory cell types and density, overall pattern, and the presence or involvement of adnexal structures were assessed in sections stained with H&E. All sections were negative for organisms within the actual footpad tissue with the anti‐BCG antibody stains. Two samples revealed a few foci of cocci on the outer surface of the ulcers. Funding: Self‐funded.     

P‐81 A retrospective study of equine sarcoidosis

The purpose of this retrospective study was to evaluate six cases of equine sarcoidosis for initial presenting symptoms, response to therapy and actual outcome. Dermatologists and dermatopathologists from Europe, the United States, Australia and Canada were contacted to obtain these six cases, as this is a rare disease. Signalment, clinical signs, histological findings, clinical management and outcome were determined via a questionnaire and compared to former reports. There was no age or breed predilection, and four of six horses were geldings. Age of onset ranged from 3 months to 17 years. Onset of the disease was insidious or rapid. Interestingly, in five of six cases, scaling began on the trunk (girth and shoulder). Scaling, crusting and alopecia were seen in all six horses. In one horse, clinical signs of systemic disease were reported and included intermittent fever, prescapular lymphadenopathy, depression, poor body condition and nasal discharge. Treatment included phenylbutazone, deworming agents, antibiotics, short‐term low‐dose corticosteroids, and 1–1.5 mg/kg of prednisolone. One horse showed a partial response to trimethoprim and sulfonamide, and five of six went into clinical remission with corticosteroid treatment. Five of six horses were still alive 1 year after diagnosis; one horse was diagnosed <12 months ago. Two horses are in complete remission 4 and 8 years after diagnosis. In both horses, clinical signs recurred after cessation of therapy and went into remission again with reintroduction of treatment. Both of these horses have been in remission for several years without therapy. Funding: Self‐funded.     

P‐65 Canine cutaneous histiocytoma: morphology and morphometry

Canine cutaneous histiocytoma is a common tumor of young dogs. Nodules are single or multiple, alopecic and well demarcated. We studied 15 young dogs with cutaneous histiocytoma. Cutaneous nodules were cytologically and histologically investigated using routine techniques. The subject for morphometry was the nuclear area of histiocytes. The figures were statistically interpreted (Student's t‐test). Cytologically, histiocytes represented the largest population, being large‐sized cells. The nucleus:cytoplasm ratio was large with oval or bean‐shaped nuclei and a fine arrangement of chromatin. The cytoplasm was discrete and basophilic, or abundant and foamy. Five regressive stages were histologically described. Stage 1 was represented by dermal and hypodermal histiocyte proliferation, covered by an intact, uninfiltrated and atrophic epidermis. Epidermal ulcers and necrotizing foci with neutrophilic, lymphocytic and plasma cell infiltrations occurred in Stages 2, 3 and 4. Stage 5 looked like a chronic dermatitis. In Stage 1, the nuclear area was the smallest (4615 ± 62 pixels) with a small coefficient of variation (14.28%), proving a homogeneous population. Stage 2 histiocytes had a larger and more heterogeneous nuclear area (6116 ± 130 pixels) with a 21.12% coefficient of variation. In Stage 3, the average nuclear area (6431 ± 115 pixels) was larger than that for Stage 2 and had a 19.18% coefficient of variation. There were no significant differences between the nuclear areas of histiocytes from Stages 2 and 3; however, significant differences occurred between Stages 1 and 2, and between Stages 1 and 3. Funding: Self‐funded.     

P‐13 Dermatophytosis in domestic cats: treatment with lufenuron

Preliminary studies showed that lufenuron inhibits chitin synthesis, a dermatophyte cell wall constituent, and may be effective in the treatment of dermatophytosis. Our purpose was to evaluate the efficacy of lufenuron in the treatment of feline dermatophytosis. Forty‐six cats (Persians and mixed‐breed cats from 1‐month to 4‐years old) naturally infected with Microsporumcanis were included in this study. Fifteen cats were treated isolated in cages in the veterinary hospital and 31 were treated in their home environment (some with access to the outdoors). Dermatophyte skin lesions were seen in 29 animals while 17 other cats were asymptomatic carriers. Wood's lamp, direct microscopic examination of hairs, fungal culture and skin biopsies were used for the diagnosis. Affected cats and all in‐contact animals received lufenuron at a dose of 120 mg/kg every 21 days for four treatments. Of the 29 symptomatic cats treated with lufenuron, 70% recovered within 21 days and 28% within 42 days of initiation of therapy. One cat had only partial recovery and another was euthanized. Negative fungal culture was recorded only after the fourth dose of lufenuron in 98% of affected cats and 100% of asymptomatic carriers. There was no difference in clinical response to lufenuron between the cats treated in their home environment and those treated in the veterinary hospital. Side effects were not observed, thus the drug proved to be safe and effective for the treatment of dermatophytosis. Funding: Novartis.     

FC‐21 Efficacy of topical tacrolimus ointment for treatment of plantar fistulae in German shepherd dogs

The objective of this open pilot study was to evaluate the efficacy of topical tacrolimus ointment for treatment of plantar fistulae in German shepherd dogs. Seven dogs (four males, three females) were included. All subjects had a 6‐month to 2‐year history of plantar fistulae involving the plantar aspect of two to four metatarsi/metacarpi. No other skin lesions were present and the dogs appeared otherwise healthy. Before treatment with tacrolimus, all dogs received antibiotics for 4–8 weeks. Hair was clipped to visualise the lesions. The presence of erythematous papules, oedema and fistulae was recorded for each foot. All dogs served as their own controls. Dogs with four legs involved had one front and one hind leg treated. Dogs with two to three feet affected had only one foot treated. Tacrolimus 0.1% ointment (Protopic^®) was applied twice daily onto the site of lesions. Partial improvement of treated lesions was seen in all cases within 3 weeks. After 6 weeks, treated lesions were in complete remission in four dogs, while the other three subjects had palpable but invisible lesions. Signs had not improved on the untreated legs. Follow‐up varied between 4 months and 2 years. Lesion remission persisted in six dogs with the intermittent application of tacrolimus. Adverse effects of treatment were not seen. In conclusion, the application of topical tacrolimus seems to provide a safe and effective treatment option for plantar fistulae in German shepherd dogs. Funding: Self‐funded.     

Efficacy of topical administration of eprinomectin for treatment of ear mite infestation in six rabbits

Six rabbits naturally infested with Psoroptes cuniculi were treated topically on the skin at the base of the neck with 0.5 mg kg(-1) of 0.5% pour-on eprinomectin for cattle, twice at 14-day intervals. Efficacy of the drug was based on the disappearance of clinical signs and the absence of live mites for a period of 6 weeks. Clinical improvement was seen within 3 days of the first application; however, complete recovery of clinical signs and elimination of mites in 5/6 rabbits did not occur until the end of the study. No adverse reactions attributable to eprinomectin treatment were observed during the observation period. Results of this trial indicated that eprinomectin was partially effective in the treatment of psoroptic mange in rabbits.     

P‐36 Juvenile idiopathic nasal scaling in three Bengal cats

Affected cats were three Bengals, one male and two females, whose age at onset of lesions ranged from 13‐ to 20‐weeks old. Nasal planum scaling progressed to thick crusting, consequent exfoliation and exposure of underlying erosions. No signs of pruritus or pain were present but mild respiratory signs were noticed. In all cats, haematology and biochemistry were normal, they were FIV and FeLV negative, PCR for herpesvirus, calicivirus and Chlamydia were negative, and viral isolation for calicivirus and herpesvirus was negative. Wood's lamp examination was negative, as were bacterial and fungal cultures. Cytology showed exfoliating keratinocytes. A skin biopsy taken from one case showed no significant changes. Biopsies from the nasal planum of four dead cats with nondermatological conditions (controls) were collected for comparative studies. Morphometry to record the percentage of the granular layer (GL) and stratum corneum (SC) on the total thickness of the epidermis of the nasal planum was performed. The GL and SC accounted for 10.2 and 21.7% of the epidermal thickness in the affected cat, compared to 18.3 and 20.2%, respectively, in the controls. A significant reduction (P < 0.02) of the SC thickness was detected in the affected cat compared to controls. No treatment was instituted as all cats underwent complete (two cats) or nearly complete (one cat) resolution. The reported cases share the same breed, age at onset, type of lesions and a similar outcome. A reduction of the SC thickness in one of the affected cats was recorded. Therefore, an underlying congenital condition is suspected that manifests with high epidermal cell turnover and normal keratinization. Funding: Self‐funded.