Double-blind pilot study on the effects of ketoconazole on intradermal skin test and leukotriene C4concentration in the skin of atopic dogs

Canine atopic dermatitis: detailed guidelines for diagnosis and allergen identification

BACKGROUND

Canine atopic dermatitis (AD) is a common, genetically predisposed, inflammatory and pruritic skin disease. The variation in clinical presentations, due to genetic factors, extent of the lesions, stage of the disease, secondary infections, as well as resemblance to other non-atopic related skin diseases, can complicate a diagnosis of canine AD. A sub-group of the International Committee for Allergic Diseases in Animals (ICADA) was tasked with the development of a set of practical guidelines that can be used to assist practitioners and researchers in the diagnosis of canine AD. Online citation databases and abstracts from international meetings were searched for publications related to the topic, and combined with expert opinion where necessary. The final set of guidelines was approved by the entire ICADA committee.

RESULTS

A total of 81 publications relevant for this review were identified. The guidelines generated focus on three aspects of the diagnostic approach: 1. Ruling out of other skin conditions with clinical signs resembling, or overlapping with canine AD. 2. Detailed interpretation of the historical and clinical features of patients affected by canine AD. 3. Allergy testing by intradermal versus allergen-specific IgE serum testing.

CONCLUSIONS

The diagnosis of canine AD is based on meeting clinical criteria and ruling out other possible causes with similar clinical signs. Flea combing, skin scraping and cytology should be performed, where necessary, as part of a thorough work-up. Elimination diet trials are required for patients with perennial pruritus and/or concurrent gastrointestinal signs. Once a clinical diagnosis of canine AD is made, allergy testing can be performed to identify potential causative allergens for allergen-specific immunotherapy.

Evidence-based veterinary dermatology: a systematic review of interventions for Malassezia dermatitis in dogs

The aim of this systematic review was to evaluate the efficacy of antifungal treatments for Malassezia dermatitis in dogs and, when possible, to propose recommendation for or against their use. Electronic searches were carried out using PubMed MEDLINE(R), CABDirect and CONSULTANT database. The volumes of Advances in Veterinary Dermatology, the proceedings of ESVD/ECVD and AAVD/ACVD congresses were hand-searched for studies relevant to this review. All articles and book chapters discussing treatment of Malassezia dermatitis were scanned for additional citations. Lastly, a request was sent to the Vetderm Listserv to share recent clinical trials. The analysis evaluated study design, methodology quality, subject enrolment quality, type of interventions and outcome measures. The searches identified 35 articles, and 14 trials that fulfilled the following selection criteria: (i) in vivo clinical trials, (ii) dogs showing clinical lesions of Malassezia dermatitis and (iii) enrolment of at least five dogs. Among these, only eight studies fulfilled the following additional criterion: (iv) prospective in vivo clinical trials reporting clinical and mycological outcome measures. A total number of 14 different treatment protocols included four blinded, randomized and controlled trials (quality of evidence grade A), four controlled studies lacking blinding and/or randomization (grade B), five open uncontrolled trials (grade C) and one descriptive study (grade D). This systematic review allowed us to recommend, with good evidence, the use of only one topical treatment of Malassezia dermatitis (2% miconazole nitrate +2% chlorhexidine, twice a week for 3 weeks) and with fair evidence the use of two systemic treatments with azole derivatives (ketoconazole, 10 mg kg(-1) day(-1) and itraconazole, 5 mg kg(-1) day(-1) for 3 weeks).

The ACVD task force on canine atopic dermatitis (XVII): intradermal testing

Intradermal testing has been practiced for decades in human and veterinary medicine. The primary utility of intradermal testing is in the demonstration of IgE-mediated allergen hypersensitivity. The presence of a positive reaction on an intradermal test is not always indicative of allergy, as it may sometimes be an indication of sub-clinical hypersensitivity. Despite its widespread use by veterinary dermatologists, the usefulness of the intradermal test would be greatly enhanced by the use of standardized allergen extracts and homogeneous criteria for the interpretation of results. Irrespective of these shortcomings, intradermal testing is regarded as a valuable tool in the demonstration of allergen-specific hypersensitivity when performed according to accepted guidelines.

The ACVD task force on canine atopic dermatitis (XIX): general principles of therapy

The treatment of canine atopic dermatitis is multifaceted and consists of a combination of actions that include the use of allergen avoidance, anti-inflammatory agents, allergen-specific immunotherapy and antimicrobial drugs. The importance and order of these treatment steps vary from patient to patient. General recommendations for each of the therapeutic steps are highlighted in this paper. Specific details are covered in other papers of this issue.

Update on the role of leukotrienes in the pathogenesis of atopy: a comparative review

The pathogenesis of atopic disease (AD) is controversial in humans and dogs. In humans, leukotrienes (LT) are thought to play an important role in this disease and LT inhibitors are commonly used as treatment for AD. Leukotrienes are a heterogeneous group of biologically active compounds that mediate many aspects of inflammatory and allergic reactions. This paper will review the role of LT in atopic disease in a comparative manner. Leukotriene inhibitors and their therapeutic use in the management of atopic disease in humans and dogs are discussed.

Sulphido-leukotriene production from peripheral leukocytes and skin in clinically normal dogs and house dust mite positive atopic dogs

Pathogenesis of canine atopy has not been completely elucidated. In humans, sulphido-leukotrienes (s-LT) play a role in atopy, and increased production of s-LT occurs in the skin and peripheral leukocytes after allergen challenge. The study population included 16 clinically normal and 13 atopic dogs. All atopic dogs had in common a positive reaction (4+) to the intradermal injection of house dust mite (allergen of reference). Blood samples and skin biopsies were collected. Sulphido-LT synthesis by peripheral leukocytes after stimulation was measured, and no statistically significant difference was found between clinically normal and atopic dogs. Sulphido-LT concentrations in skin samples from stimulated and unstimulated sites were measured, and no statistically significant difference was detected between clinically normal and atopic dogs or between lesional and nonlesional skin within the atopic group. Clinical signs of atopic dogs were graded by owners and no correlation was found between their severity and cutaneous concentrations of s-LT. In this study there was no increase in s-LT synthesis in atopic dogs.

Malassezia pachydermatis: a review

Malassezia pachydermatis is of importance in both veterinary and human medicine. Its taxonomic status and physiological characteristics are now better understood. Skin disease associated with this lipophilic yeast is now commonly recognized, especially in dogs. However, further studies are required to elucidate the mechanisms which allow this yeast to proliferate and induce disease. Skin colonization is common in pet carnivores which consequently constitute a source of M. pachydermatis for susceptible humans. In the future, the development of efficient typing systems should allow better understanding of the transmission mechanisms.