Evaluation of adrenal function in small-breed dogs receiving otic glucocorticoids.

The objectives of this study were to evaluate adrenal function after otic glucocorticoid [Tresaderm (dexamethasone) and Otomax (betamethasone)] therapy in small-breed dogs without evidence of otitis and to evaluate the length of time needed for resolution of adrenal suppression after discontinuation of treatment. Fourteen clinically healthy, privately owned, small-breed dogs with normal ears and normal adrenocorticotropin (ACTH) stimulation tests were assigned to one of two treatment groups, receiving one of the medications at the manufacturer's recommended dosage twice daily for 2 weeks. All of the dogs in the betamethasone treatment group had normal ACTH stimulation tests after 2 weeks of treatment. In contrast, 5/7 (71.43%) in the dexamethasone group, had suppressed adrenocortical responses to exogenous ACTH. Three of these five dogs (42%) returned to normal values 1 week after ceasing the medication and two (28.57%) returned to normal values 2 weeks after ceasing the medication. In conclusion, it appears that adrenal function can be suppressed for up to 2 weeks in dogs receiving otic dexamethasone. A follow-up study repeating this work in dogs with inflamed ears is needed before further clinical recommendations can be made.

Pilot study to assess the effects of early flea exposure on the development of flea hypersensitivity in cats.

This pilot study was to determine if early oral flea exposure reduces the incidence of flea allergy dermatitis (FAD) in cats. Eighteen kittens, assigned to three groups, received no flea exposure, oral flea exposure or flea infestation for 12 weeks. Then all the kittens were exposed continually to fleas for 31 weeks. Sensitization was monitored using intradermal testing (IDT), in vitro measurement of anti-flea saliva immunoglobulin E (IgE) and development of FAD. There was no statistically significant difference between groups in IDT reactions, in vitro data or clinical scores. The development of FAD was not associated with the presence of anti-flea saliva IgE. However, the development of a delayed reaction to flea bite was associated with symptoms after flea exposure. Although not statistically significant, the FAD scores in the oral group were lower than in the controls. Further studies are required to determine the role of oral flea exposure in the development of FAD in cats.

A Scoring Index for Clinical Signs of Flea Allergy Dermatitis in the cat.

This article describes the development, application, and validation of a scoring index for assessment of clinical signs in cats with flea allergy dermatitis (FAD). The Scoring Index for Clinical Signs of FAD was based on the evaluation and scoring of five signs over five anatomic areas, which is similar to the psoriasis area and severity index (PASI), a commonly used scoring method in human dermatology. The Scoring Index for Clinical Signs of FAD was used by different veterinarians to assess several groups of flea allergic research cats with varying signs of FAD. Analysis of the data shows a significant correlation and repeatability between investigators, making this a very useful scoring index.

Clinical efficacy of selamectin for the control of fleas on dogs and cats.

The topical endectocide selamectin (Revolution, Pfizer Animal Health) was evaluated in seven veterinary dermatology specialty clinics for its ability to control fleas on 75 dogs and 46 cats from single- and multiple-animal households. All animals were treated on days 0, 30, and 60 with a minimum unit dose of 6 mg/kg of selamectin(h) applied to the skin in a single spot at the base of the neck in front of the scapulae. The product was applied according to label instructions, and the use of other topical or environmental flea control products was prohibited during the study. Efficacy was assessed by percentage reductions in geometric mean flea comb counts. The reductions in flea numbers for dogs and cats combined were 90.6%, 97.0%, and 98.0% on days 30, 60, and 90, respectively, compared with day 0. This study demonstrates that selamectin, applied at 30-day intervals to dogs and cats, effectively controls flea infestations without other flea control products in single- and multiple-animal households.

A description of cutaneous-subcutaneous pythiosis in fifteen dogs.

Information regarding signalment, duration of clinical signs, history of swimming, results of CBC and serum biochemical analyses, biopsy findings and mycological results, together with treatments and outcome, was retrieved from the medical records of 15 dogs with a diagnosis of pythiosis made between 1985 and 1995 at the Colleges of Veterinary Medicine, North Carolina State University and the University of Florida. Most of the dogs were young (median age 22 months) and represented larger breeds (> 20 kg). Lesions were characteristically chronic, ulcerated, and nodular with multiple draining tracts on the limbs, thoracic wall or perineal regions. The median duration of these lesions was 3 months with a range of 2 weeks-6 months. Seven dogs had a history of swimming. Peripheral eosinophilia was observed in 14 of the dogs. Cytological evaluation of discharge, aspirates, or impression smears made from biopsy specimens revealed hyphae in five of 11 dogs (45%). Histopathological evaluation using the Gomori Methenamine-Silver (GMS) stain was the most useful test for providing presumptive evidence of cutaneous pythiosis. Immunotherapy or antifungal therapy using either amphotericin B, liposomal nystatin, itraconazole, or ketoconazole were all unsuccessful. The only dog to survive underwent amputation of the affected limb; thus, the prognosis for cutaneous pythiosis in the dog is poor.

Intradermal reactivity to various insect and arachnid allergens among dogs from the southeastern United States.

OBJECTIVE: To compare cutaneous reactivity to insect and arachnid allergens in clinically normal (control) and allergic dogs in the southeastern United States. DESIGN: Prospective, controlled study. ANIMALS: 26 clinically normal dogs and 82 allergic dogs from the southeastern United States. PROCEDURE: Intradermal skin testing with various dilutions of 13 insect and arachnid allergens was performed on control dogs to establish skin threshold concentrations (ie, concentrations to which < 25% of the dogs had positive reactions). These established threshold concentrations were then used to test allergic dogs for reactivity. Prevalence of single and multiple insect and arachnid reactions were determined. RESULTS: Flea allergen was the only allergen that caused a significantly higher prevalence of positive reactions in allergic dogs than in control dogs. CLINICAL IMPLICATIONS: Flea hypersensitivity is the most important arthropod hypersensitivity in dogs. The importance of reactivity to insect and arachnid allergens other than flea allergen can be determined only when prevalence of positive reactivity has been determined in an appropriate regional control group of dogs.

Distribution and appearance of elastic fibers in the dermis of clinically normal dogs and dogs with solar dermatitis and other dermatoses.

OBJECTIVE: To determine the distribution and amount of elastic fibers in the dermis of clinically normal dogs and dogs with dermatoses, particularly solar dermatitis. DESIGN: Skin specimens from 7 anatomic sites were obtained from 19 clinically normal dogs after euthanasia to evaluate the normal distribution of elastic fibers. Biopsy specimens also were obtained from 34 dogs with dermatoses, including 16 with solar dermatitis. Tissue sections were stained with H&E, Verhoeff-van Gieson, and periodic acid-Schiff. ANIMALS: 19 clinically normal dogs and 34 dogs with dermatoses. PROCEDURE: Numbers of elastic fibers were graded subjectively. Comparisons between clinically normal dogs and dogs with dermatoses were made. RESULTS: Normal elastic fibers were present in low numbers in the dermis of adult dogs, regardless of anatomic site or presence or severity of dermatitis. Condensed elastotic material was visualized in only 2 dogs with solar dermatitis. In both dogs, the elastotic material was Verhoeff-van Gieson and periodic acid-Schiff stain positive but was not visible with H&E stain. The most frequent histopathologic finding in the dermis of dogs with solar dermatitis was superficial dermal fibrosis. CONCLUSIONS: The dermis of clinically normal dogs does not contain abundant elastic fibers. Alterations of elastic fibers in dogs with solar dermatitis are rare. Superficial dermal fibrosis may be a better indicator of solar damage.

Adverse side effects of oral antibacterial therapy in dogs and cats: an epidemiologic study of pet owners' observations.

This epidemiologic study surveyed pet owners for observations of adverse reactions to oral antibacterials which were prescribed to outpatients at a university teaching hospital. Multiple questions were asked of all clients whose dog or cat was treated during the 18-month study. The questionnaire was designed prospectively to define those reactions that clearly seemed to be medication related. In this study, owners noted a significant number of adverse side effects with erythromycin stearate administration to dogs. Trimethoprim-sulfadiazine was used most often in dogs but did not result in a substantial number of adverse reactions.

Disseminated subcutaneous Mycobacterium fortuitum infection in a dog.

A 15-month-old 27.7-kg sexually intact male Doberman Pinscher was examined because of multiple subcutaneous abscesses on the neck, trunk, and limbs that developed 2 months after a dog bite and were refractory to antibiotic treatment. Incubation of a biopsy specimen at 37 C on a Lowenstein-Jensen agar slant for 8 days yielded growth of a Runyon's Group IV mycobacterium, and disseminated subcutaneous Mycobacterium sp infection was diagnosed. The organism was identified as M fortuitum, and was susceptible to amikacin, doxycycline, cefoxitin, minocycline, trimethoprim/sulfadiazine, and sulfisoxazole. Lesions resolved after 8 months of treatment with doxycycline (5 mg/kg of body weight, PO, q 12 h). The cause of dissemination was unknown; however, delay in debridement of the bite wound and corticosteroid use in initial wound management may have potentiated dissemination.

Comparison of the efficacy of cefadroxil and generic and proprietary cephalexin in the treatment of pyoderma in dogs.

We compared efficacy of cefadroxil and generic and proprietary cephalexin in treatment of pyoderma in dogs. Forty-four dogs were randomly assigned to receive 1 of the 3 preparations at 22 to 35 mg/kg body weight, every 12 hours. Dogs were examined at the conclusion of treatment period and assessed as to degree of improvement. All 3 cephalosporins were effective and safe antibiotics for the treatment of pyoderma in dogs.

Focal metatarsal fistulas in five dogs.

Focal metatarsal fistulas were identified in 5 young adult German Shepherd Dogs or dogs of similar breeding. A specific cause was not identified when biopsy specimens for culture and histologic examination were evaluated. Corticosteroid treatment was beneficial for some lesions. The dogs did not have other dermatologic diseases, and the clinical course, although chronic, was generally benign.

Serum and skin concentrations after multiple-dose oral administration of trimethoprim-sulfadiazine in dogs.

Six healthy adult mixed breed dogs were each given 5 oral doses of trimethoprim (TMP)/sulfadiazine (SDZ) at 2 dosage regimens: 5 mg of TMP/kg of body weight and 25 mg of SDZ/kg every 24 hours (experiment 1) and every 12 hours (experiment 2). Serum and skin concentrations of each drug were measured serially throughout each experiment and mean serum concentrations of TMP and SDZ were determined for each drug for 24 hours (experiment 1) and 12 hours (experiment 2) after the last dose was given. In experiment 1, mean serum TMP concentration was 0.67 +/- 0.02 micrograms/ml, and mean skin TMP concentration was 1.54 +/- 0.40 micrograms/g. Mean serum SDZ concentration was 51.1 +/- 12.2 micrograms/ml and mean skin SDZ concentration was 59.3 +/- 9.8 micrograms/g. In experiment 2, mean serum TMP concentration was 1.24 +/- 0.35 micrograms/ml and mean skin TMP concentration was 3.03 +/- 0.54 micrograms/g. Mean serum SDZ concentration was 51.6 +/- 9.3 micrograms/ml and mean skin SDZ concentration was 71.1 +/- 8.2 micrograms/g. After the 5th oral dose in both experiments, mean concentration of TMP and SDZ in serum and skin exceeded reported minimal inhibitory concentrations of TMP/SDZ (less than or equal to 0.25/4.75 micrograms/ml) for coagulase-positive Staphylococcus sp. It was concluded that therapeutically effective concentrations in serum and skin were achieved and maintained when using the manufacturer's recommended dosage of 30 mg of TMP/SDZ/kg (5 mg of TMP/kg and 25 mg of SDZ/kg) every 24 hours.

Cholinergic pruritus in a horse.

An 8-year-old gelding, with a 1-year history of intense pruritus only after exercise, was diagnosed as having cholinergic pruritus. Provocative testing, using exercise and hot-water baths to increase core body temperature, assisted in the diagnosis. Cholinergic pruritus in human beings is a variant of the more common syndrome, cholinergic urticaria, which is characterized by intense pruritus and pinpoint urticaria. With cholinergic pruritus, intense itching results without urticaria. Specific diagnostic laboratory tests have not been developed.

Validity of skin testing for diagnosis of food allergy in dogs.

One hundred suspected allergic dogs were skin-tested with 9 food extracts, in addition to other inhalant and insect allergens. Forty-eight of the dogs had +2 or greater intradermal reactions to 1 or more food extracts at concentration of 1,000 protein nitrogen units/ml. Thirty of the food extract-positive dogs were fed a restrictive hypoallergenic diet. Of these 30 dogs, 3 improved, then allergy signs worsened when they were challenge-exposed with the original diet. Fifty-two dogs did not have skin test reactivity to any of the 9 food extracts. Of these 52 dogs, 35 were fed a restrictive diet. Six improved, then allergy signs worsened when dogs were challenge-exposed with the original diet. Skin-testing with selected allergenic food extracts was not useful in identifying food-sensitive dogs.

Comparison of serum cortisol concentration before and after intradermal testing in sedated and nonsedated dogs.

Serum cortisol concentration was evaluated in 71 dogs before and after a stressful procedure was performed. Thirty dogs were skin tested with sedation (group S), 21 dogs were skin tested without sedation (group NS), and 20 dogs had other dermatologic procedures performed (group C). Group-S dogs had significant (P less than 0.001) decrease in serum cortisol concentration after skin testing, compared with baseline values. In contrast, dogs of groups NS and C had significant (P less than 0.001) increase in poststress serum cortisol concentration. Mean cortisol concentration after stress was significantly lower for dogs of group S, compared with that for dogs of the other 2 groups. The second part of the analysis consisted of determining the number of false-negative skin test results for dogs of groups S and NS and comparing these with serum cortisol concentration. Difference in the number of suspected atopic dogs with negative skin test results (false-negative) was not evident between groups S and NS. Also, difference was not apparent between cortisol concentration in dogs that had positive or false-negative skin test results in either group. This finding indicates that high serum cortisol concentration does not affect results of skin testing in suspected atopic dogs.

Effects of sedation on intradermal skin testing in flea-allergic dogs.

Effects of 4 commonly used sedatives on the wheal-and-flare response to histamine and flea antigen were evaluated in 8 flea-allergic Beagles. Skin testing was performed in 12 separate occasions, 3 to 4 days apart. Twelve intradermal injections were given during each skin test: 5 doubling dilutions of histamine phosphate, 6 doubling dilutions of flea antigen, and a phosphate-buffered saline solution (negative control). Of the 12 intradermal skin tests, 8 were control tests performed on nonsedated dogs. The remaining 4 tests were performed on dogs sedated with xylazine, ketamine and valium combination, acepromazine, or oxymorphone. Oxymorphone had the most profound effect on skin test results, significantly (P less than 0.05) decreasing skin responsiveness in 8 of 11 test sites (by objective evaluation) and in 5 of 11 test sites (by subjective evaluation). Xylazine sedation enhanced skin test results in 4 of 11 test sites (by objective evaluation) and in 1 of 11 test sites (by subjective evaluation). In non instance did xylazine significantly decrease skin responsiveness to histamine or flea antigen. Xylazine is the recommended sedative in dogs when sedation is necessary for intradermal skin testing.

Lack of autologous tissue transmission of eosinophilic plaques in cats.

Autologous tissue transmission of spontaneously developing feline eosinophilic plaques was attempted in 5 cats. Macerated tissue from the plaque was vigorously rubbed onto 2 scarified skin sites in each cat. The inoculated areas were observed daily for 30 days. During that time, no clinical or histologic evidence of transmission was found.

Contact dermatitis.

Allergic contact dermatitis and irritant contact dermatitis in the small animal may result in clinical lesions with similar anatomical locations. Allergic contact dermatitis is generally noted in ventral and lightly haired regions as a papular, erythematous, and sometimes vesicular dermatitis. It is intensely pruritic and is the result of many months (and usually years) of exposure to the contact allergen. Total avoidance of the allergenic substance is the only successful long-term management. Irritant contact dermatitis occurs when an irritating substance is applied to the skin. It is a sequela that would occur in the majority of a population having contact with the compound. It is generally more painful than pruritic. Removal of the irritant will permit resolution of the signs.

Toxicity of high doses of griseofulvin in cats.

Eight adult cats were treated with griseofulvin (110 to 145 mg/kg of body weight) daily for 11 weeks; 2 control cats were given a gelatin capsule daily. Hemograms and hepatic enzyme activities were monitored weekly for all cats. Bone marrow examinations were performed before administration of the drug and twice during the study. Cats were observed for untoward clinical effects. Signs of toxicosis (clinical, hematologic, or hepatic) were not found at any time during, or at the cessation of, the study. Although the sample number of treated cats was small, it was concluded that hematologic or hepatic abnormalities that develop with the use of high-dose griseofulvin treatment may be an idiosyncratic reaction found only in a few cats.