Evaluation of three different histamine concentrations in intradermal testing of normal cats and attempted determination of 'irritant' threshold concentrations for 48 allergens.

The purpose of this study was to determine the optimal histamine concentration and 'irritant' allergen threshold concentrations in intradermal testing (IDT) in normal cats. Thirty healthy cats were tested with three different histamine concentrations and four different concentrations of each allergen. The optimal histamine concentration was determined to be 1: 50,000 w/v (0.05 mg mL(-1)). Using this histamine concentration, the 'irritant' threshold concentration for most allergens was above the highest concentrations tested (4,000 PNU mL(-1) for 41 allergens and 700 PNU mL(-1) for human dander). The 'irritant' threshold concentration for flea antigen was determined to be 1:750 w/v. More than 10% of the tested cats showed positive reactions to Dermatophagoides farinae, Dermatophagoides pteronyssinus, housefly, mosquito and moth at every allergen concentration, which suggests that the 'irritant' threshold concentration for these allergens is below 1,000 PNU mL(-1), the lowest allergen concentration tested. Our results confirm previous studies in indicating that allergen and histamine concentrations used in feline IDT may need to be revised.

Determination of threshold concentrations of allergens and evaluation of two different histamine concentrations in canine intradermal testing.

The purpose of this study was to determine the optimal histamine concentration and allergen threshold concentrations for canine intradermal testing. Thirty healthy dogs were tested using two different concentrations of histamine and four different concentrations of each allergen. The optimal histamine concentration was determined to be 1:10 000 w/v. The threshold concentration was at least 1750 PNU/mL for all tested grasses, weeds, trees, moulds and insects, except for fleas which was as least 1:500 w/v. For Dermatophagoides pteronyssinus, the optimal threshold concentration was 250 PNU/mL, whereas for Dermatophagoides farinae and Tyrophagus putrescentiae, it was 100 PNU/mL. Threshold concentration for all epidermals except human dander was at least 1250 PNU/mL. The optimal threshold concentration for human dander was 300 PNU/mL. Our results suggest that the currently used 1:100 000 w/v concentration of histamine and the 1000 PNU/mL concentration for most grasses, weeds, trees, moulds, epidermals and insects may not be appropriate for canine intradermal testing.

Immunotherapy for treatment of multicentric cutaneous pythiosis in a dog.

A 4-year-old Labrador Retriever was referred for evaluation of 2 ulcerative nodular cutaneous lesions. One lesion was located on the medial aspect of the right carpus; the other was located on the medial aspect of the left tarsus. The dog had spent its entire life in the southeastern part of the United States and approximately half of its time outdoors with free access to a nearby lake. Histologic examination of full-thickness wedge biopsy specimens from both lesions revealed severe, multifocal, puruloeosinophilic to pyogranulomatous deep dermatitis with intralesional filamentous structures, fibroplasia, and neovascularization. Examination of sections stained with Gomori methenamine silver stain revealed a moderate number of wide, bulbous, irregularly septate, branching hyphae. Results of an immunodiffusion test and an ELISA for anti-Pythium insidiosum antibodies were positive. Amputation was eliminated as a treatment option because lesions involved 2 limbs. Long-term systemic antifungal treatment was also rejected because of the cost, lack of therapeutic effect in many cases, and potential for adverse effects. The dog was treated with 2 doses of an anti-P insidiosum vaccine administered 2 weeks apart. One month later, the lesions were nearly completely healed, and values obtained via the immunodiffusion test and ELISA had decreased. Results of the immunodiffusion test and ELISA were negative 1 year later, and the dog had not had any recurrences.

Effect of topical application of fipronil in cats with flea allergic dermatitis.

OBJECTIVE: To determine whether topical application of a 10% fipronil solution would control signs of flea allergic dermatitis in cats housed under natural conditions. DESIGN: Multicenter open clinical trial. ANIMALS: 42 client-owned cats with flea allergic dermatitis. PROCEDURES: Study cats along with all other cats and dogs living in the same houses were treated with 10% fipronil solution topically on days 0, 30, and 60. Flea counts and clinical assessments were performed on study cats on days 0, 14, 30, 60, and 90. RESULTS: Percentage reductions in geometric mean flea counts on days 14, 30, 60, and 90, compared with day-0 geometric mean count, were 75, 73, 85, and 94%, respectively. Pruritus score was significantly improved at each examination after day 0, and pruritus was reduced or eliminated in 31 of 40 (78%) cats at the final examination. Similarly, scores for severity of miliary dermatitis and alopecia were significantly improved at each examination, except for alopecia score on day 14. Overall treatment efficacy, assessed on day 90, was excellent for 28 (70%) cats, good for 6 (15%), moderate for 3 (7.5%), and poor for 3 (7.5%). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that monthly topical application of fipronil is effective for treatment of flea allergic dermatitis in cats housed under natural conditions.

Evaluation of topically applied enilconazole for the treatment of dermatophytosis in a Persian cattery.

Many Persian catteries have long-standing dermatophyte infections and are particularly difficult to treat. Enilconazole is a topical antifungal agent that has demonstrated good efficacy in recent studies. Twenty-two Persian cats naturally infected with Microsporum canis in a breeding cattery were treated with topical 0.2% enilconazole and monitored for 180 days. The treatments were repeated every 3 days for a total of eight applications. All the cats improved clinically and became culture negative by day 28. By day 180, four cats had developed clinical dermatophytosis and all cats had positive fungal cultures. In this study, topical 0.2% enilconazole was generally well tolerated but may have caused hypersalivation, idiopathic muscle weakness and slightly elevated serum alanine aminotransferase (ALT) concentrations. This study suggests that enilconazole may be used safely with little risk to the young, aged and gravid animals.

Dermatophyte granulomas caused by Trichophyton mentagrophytes in a dog.

Multiple, dermal and subcutaneous nodules developed in a young female Manchester Terrier dog that had a chronic history of superficial dermatophytosis. Skin biopsy specimens of the nodules revealed granulomatous inflammation in the deep dermis and subcutis with branching fungal organisms. Cultures of multiple biopsy specimens from the nodules all yielded Trichophyton mentagrophytes. The lesions in this dog were similar to granulomatous dermatophytosis, a skin disease that has been reported in Persian cats and one Yorkshire Terrier dog.

Daily ivermectin for treatment of generalized demodicosis in dogs.

Abstract Twelve dogs with generalized demodicosis were treated with oral administration of ivermectin, 0.4 mg kg-1 of body weight given once every 24 h. Results of skin scrapings were used to determine whether administration of ivermectin should be continued or stopped. Dogs that were free of clinical signs of demodicosis 12 months after administration of ivermectin was discontinued were considered cured. Five dogs were cured. The medían duration of treatment was 15 weeks (range 5-21 weeks). Seven dogs were failures, with five relapsing 3-11. 5 months after treatment was stopped, and two having persistent demodicosis in spite of treatment. Mild ivermectin toxicosis developed in one dog after 5 weeks of treatment; side-effects resolved shortly after the treatment was stopped. Resumen Se trataron doce perros con demodicosis generalizada con ivermectina oral, 0.4 mg/Kg de peso corporal una vez cada 24 h. Se realizaron raspados cutáneos para déterminar si debia retirarse o continuar con la administración de ivermectina. Se consideraron curados aquellos perros sin sintomatologia de demodicosis 12 meses después de retirar la terapia con ivermectina. La duración medía del tratamiento con ivermectina fue de 15 semanas (rango de 5-21). Se fracasó en siete perros, con cinco recidivas a los 3-11, 5 meses después de parar la terapia y dos con demodicosis persistente a pesar del tratamiento. Un perro desarrolló una toxicosis leve a la ivermectina a las 5 semanas del tratamiento; los efectos secundarios desaparecieron al poco de retirar el tratamiento. [Medleau, L., Ristic, Z., McElveen, D.R. Daily ivermectin for treatment of generalized demodicosis in dogs (Administración díaria de ivermectina para el tratamiento de le demodicosis generalizada en el perro). Veterinary Dermatology 1996; 7: 209-212.] Résumé Douze chiens présentant une démodécie généralisée fürent traités par administration orale d'ivermectine à la dose de 0.4 mg/kg de poids une fois par jour. Les résultats des raclages cutanés servirent à déterminar la nécessité de continuer ou d'arrêter l'administration d'ivermectine. Les chiens ne présentant aucun symptôme de démodécie 12 mois après l'arrêt de l'ivermectine fürent considérés guéris. Cinq chiens fürent guéris. La durée moyenne du traitement fut de 15 semaines (intervalles de 5 à 21 semaines. Sept cas fürent des échecs, avec 5 chiens récidivant 3 à 11, 5 mois après l'arrêt du traitement, et 2 présentant une démodécie persistante malgré le traitement. Un chien a développé une intoxication modéree après 5 semaines de traitement; les effets secondaires disparaissant rapidement après l'arrêt du traitement. [Medleau, L., Ristic, Z., McElveen, D.R. Daily ivermectin for treatment of generalized demodicosis in dogs (Administration quotidienne d'ivermectine dans le traitement de la démodécie généralisée chez le chien). Veterinary Dermatology 1996; 7: 209-212.] Zusammenfassung Zwölf Hunde mit generalisierter Demodikose wurden mit einer oralen Verabreichung von Ivermectin in der Dosierung von 0, 4 mg/kg Körpergewicht einmal alle 24 Stunden behandelt. Die Ergebnisse der Hautgeschabsel dienten zur Bestimmung, ob die Verabreichung weiterhin erfolgen sollte oder abzubrechen sei. Hunde, die 12 Monate nach Ende der Ivermectin-Verabreichung frei von klinischen Symptomen der Demodikose waren, wurden als geheilt betrachtet. Fünf Hunde waren geheilt. Die mittlere Therapiedauer betrug 15 Wochen (Spannweite 5 bis 21 Wochen). Bei sieben Hunden versagte die Therapie, wobei fünf nach 3 bis 11, 5 Monaten nach Behandlungsende ein Rezidiv bekamen und zwei Tiere trotz der Therapie einer persistierende Demodikose zeigten. Bel einem Hund entwickelte sich 5 Wochen nach der Behandlung eine milde Ivermectin-Intoxikation; die Nebenwirkungen verschwanden kurz nach Abbruch der Therapie. [Medleau, L., Ristic, Z., McElveen, D.R. Daily ivermectin for treatment of generalized demodicosis in dogs (Tägliche Ivermectinverabreichung als Behandlung für Hunde mit generalisierter Demodikose). Veterinary Dermatology 1996; 7: 209-212.].