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.     

Influence of long-term treatment with tetracycline and niacinamide on antibody production in dogs with discoid lupus erythematosus

OBJECTIVE: To evaluate the effect of long-term treatment with tetracycline and niacinamide on antibody production in dogs by measuring postvaccinal serum concentrations of antibodies against canine parvovirus and canine distemper virus. ANIMALS: 10 dogs receiving long-term treatment with tetracycline and niacinamide (treatment group) and 10 healthy dogs (control group). PROCEDURE: The treatment group included 9 dogs with discoid lupus erythematosus and 1 dog with pemphigus foliaceus on long-term treatment (> 12 months) with tetracycline and niacinamide. The control group included 10 healthy dogs with no clinical signs of disease and no administered medications for the past 3 months. Blood samples were obtained from all dogs by jugular venipuncture. Serum antibody titers against canine parvovirus and canine distemper virus antigens were measured, using hemaglutination inhibition and serum neutralization, respectively, and compared between groups. RESULTS: A significant difference in antibody titers between treatment- and control-group dogs was not found. All dogs had protective antibody titers against canine distemper virus, and 8 of 10 dogs from each group had protective titers against canine parvovirus infection. CONCLUSION AND CLINICAL RELEVANCE: These results provide evidence that long-term treatment with tetracycline and niacinamide does not interfere with routine vaccinations and thus does not seem to influence antibody production in dogs.     

Results of allergen-specific immunotherapy in 117 dogs with atopic dermatitis

The success of the treatment of 117 dogs with atopic dermatitis with allergen-specific immunotherapy for up to 48 months was assessed. An excellent response (remission with exclusive immunotherapy) was recorded in 18 of the dogs, a good response (more than 50 per cent reduction in medication and improvement of clinical signs) was recorded in 57, a moderate response was recorded in 24 and a poor response in 18. The mould antigens in the allergen extract were stored in a separate vial before administration and the success rate of the immunotherapy including mould antigens was much higher than in an earlier study in which mould and pollen antigens had been stored in one vial. The success rate was not affected significantly by the age of the dogs when the disease developed, or by their age or the period for which they had shown clinical signs when the treatment began; it was also unaffected by whether pollens, moulds or dust mites were used as antigens, or by whether the offending allergens had been identified by intradermal testing or by serum testing for allergen-specific immunoglobulin E.     

Evaluation of cross-reactivity of allergens by use of intradermal testing in atopic dogs

OBJECTIVE: To examine cross-reactivity of aeroallergens in Colorado and surrounding states by evaluating concurrent positive reactions of related and nonrelated allergens of intradermal tests in dogs. SAMPLE POPULATION: Intradermal test results of 268 atopic dogs. PROCEDURE: A retrospective evaluation of skin test results for 268 dogs was performed. Pairs of closely related and nonrelated allergens were evaluated. Group 1 consisted of closely related allergens with demonstrated antibody cross-reactivity in humans. In group 2, allergens of the same plant group (ie, trees, grasses, or weeds) that were not closely related were paired. In group 3, allergen pairs were of different plant groups. Plant allergens were paired with dust mite allergens, animal dander, or mold spores in group 4. In the last group, allergens not derived from plants were paired. Data were evaluated twice by use of a different definition of a positive reaction. Significance of the difference between group means of log odds ratios was estimated by use of a boot-strap percentile confidence interval. RESULTS: Significant differences in the number of concurrent positive reactions were not found between related versus nonrelated grass, weed, or tree allergens. Significant differences in the number of concurrent positive reactions were found between plant allergens of different groups (ie, grasses, weeds, and trees) and plant allergens of the same groups, related or nonrelated, as well as between plant-derived and nonplant-derived allergens. Many dogs reacting to a specific allergen did not react to a closely related allergen at the same time. CONCLUSION: These results provide evidence against clinically relevant cross-reactivity and suggest that allergen-specific immunotherapy should be formulated on the basis of single allergen test results.     

Immunohistochemical evaluation of mononuclear infiltrates in canine lupoid onychodystrophy

Claw biopsy samples of 11 dogs with lupoid onychodystrophy were evaluated. They were stained with hematoxylin and eosin and with antibodies against CD 3 as a T-cell marker, BLA 36 and HM 57 (CD 79alpha) as B-cell markers, and lysozyme, Mac 387, and major histocompatibility complex (MHC) class II as a marker for histiocytes using an immunoperoxidase and avidin-biotin technique. Inflammatory cells were counted in five high-power fields. The inflammatory infiltrate comprised predominantly B cells and T cells. Macrophages were typically only present in small numbers. CD 3, BLA 36, lysozyme, and MHC class II preserved significant antigenicity during formalin fixation and short decalcification for 24-48 hours, whereas CD 79alpha and particularly Mac 387 seemed to be more susceptible to denaturation by the decalcification process.     

Review of 15 cases of pemphigus foliaceus in horses and a survey of the literature

The records of 15 horses with pemphigus foliaceus diagnosed on the basis of their history, clinical signs, histopathology and the exclusion of differential diagnoses were evaluated with respect to the age of onset, the clinical signs and the diagnostic tests used. There was no apparent breed predisposition. The horses' mean age was nine years, with a range from three months to 25.5 years, three were foals up to six months old and eight were nine years old or older. The most frequent lesions were scaling in 11, crusting in 10 and alopecia in 10, and they appeared most commonly on the face, neck and trunk, in 10 horses for each of these sites. The extremities were involved in nine of the horses, pruritus occurred in seven, and four of the horses had pustules. The clinical signs mostly corresponded with those described in previous reports, but signs of pain were not a prominent feature. Acantholytic cells were identified cytologically in four of six of the horses.     

Adverse effects of ketoconazole in dogs--a retrospective study

Although ketoconazole has been used extensively in dogs for the treatment of various fungal infections, information about adverse effects is mainly anecdotal. Common adverse effects in humans include dose-dependant anorexia, nausea and vomiting, allergic rashes and pruritus. Drug-induced hepatitis is very rare, but potentially fatal. The aim of this study was to evaluate the type and frequency of adverse effects associated with ketoconazole therapy in dogs treated for skin diseases and any possible influence of dosage, duration of therapy, signalment or concurrent medication. The medical records of 632 dogs treated with ketoconazole (2.6–33.4 mg/kg) were reviewed. Adverse effects occurred in 14.6% (92 dogs) and included vomiting (7.1%), anorexia (4.9%), lethargy (1.9%), diarrhea (1.1%), pruritus (0.6%), erythema (0.3%) and other adverse effects (2.5%). Of the dogs with other adverse effects, four of 16 (25%) were ataxic and three of these received concurrent ivermectin. Adverse effects were significantly more often recorded in dogs concurrently treated with ciclosporin ( P =  0.034) or ivermectin ( P =  0.007). Increased liver enzyme levels were reported rarely, and icterus was not seen in any of the dogs. However, monitoring liver enzymes during therapy is recommended, although this might not necessarily prevent severe idiosyncratic hepatotoxicity.