Proliferative, lymphocytic, infundibular mural folliculitis and dermatitis with prominent follicular apoptosis and parakeratotic casts in four Labrador retrievers: preliminary description and response to therapy.

OBJECTIVES: To describe the clinical, histopathological and immunohistochemical lesions and the response to therapy of a novel skin disease in four dogs, and to compare the lesions with those of other similar conditions. METHODS: Clinical lesions, the histopathological findings in skin biopsy samples, immunohistochemistry for CD3 and cleaved caspase-3 and the response to therapy were evaluated. RESULTS: Clinical lesions included multifocal, coalescing, verrucous, crusted papules and plaques with erythematous borders and comedones or follicular casts. Lesions were in haired skin; they occurred at the edges of paw pads and claw beds in one dog. Histopathological lesions included ortho- and more prominent parakeratotic hyperkeratosis involving follicular infundibular epithelium, with cast formation and a papillary epidermal surface. Lymphocytic exocytosis affected all strata of follicular infundibular epithelium and epidermis. Variable numbers of acidophilic shrunken keratinocytes, often bordered by lymphocytes (satellitosis), occupied the more superficial strata of the follicular infundibular epithelium and epidermis. Immunohistochemistry revealed numerous CD3+ T lymphocytes and fewer cleaved caspase-3-positive apoptotic keratinocytes in the infundibular hair follicle epithelium and epidermis, with numerous CD3+ T lymphocytes and cleaved caspase-3-positive cells in the dermis. Two dogs responded completely to therapy with ciclosporin and remained lesion free off therapy; one dog responded to therapy with prednisone, azathioprine and ciclosporin, but relapsed; and one dog was not treated. CONCLUSIONS AND CLINICAL IMPORTANCE: The cause of the lesions is unknown; the presence of intraepithelial CD3+ lymphocytes and cleaved caspase-3-positive apoptotic keratinocytes and the positive response to immunosuppressive therapy suggest an immune response directed towards unidentified antigens expressed on the surface of keratinocytes.

Development and validation of the Canine Atopic Dermatitis Lesion Index, a scale for the rapid scoring of lesion severity in canine atopic dermatitis.

BACKGROUND: The third iteration of the Canine Atopic Dermatitis Extent and Severity Index (CADESI-03) is the only tool rigorously validated for canine atopic dermatitis (CAD) lesion scoring. The CADESI-03 requires 248 evaluations, limiting its widespread use. HYPOTHESIS/OBJECTIVES: The goal of the study was to develop and validate a practical method of grading CAD lesions that requires scoring only the frequently affected body regions. ANIMALS: Fifty-seven privately owned atopic dogs were used in the study. METHODS: The Canine Atopic Dermatitis Lesion Index (CADLI) was evaluated in an open, multicentre reliability study. Validity was assessed with expert opinion (content validity) and comparison of CADLI with existing disease severity measures (construct and criterion validity). Reliability was evaluated by analysing repeated observations of each dog. Convenience was assessed in terms of the time required to complete the scale. RESULTS: The CADLI scores correlated with overall assessment scores (r = 0.60, P < 0.001, linear mixed model) and pruritus severity scores (r = 0.53, P < 0.001, linear mixed model), establishing construct validity. The CADLI was strongly correlated with CADESI-03 (r = 0.84, P < 0.001, linear mixed model), establishing criterion validity. The CADLI values obtained by two observers correlated very strongly (r = 0.91, P < 0.001), as did the repeat values for the same observer (r = 0.98, P < 0.001). The mean time to complete the CADLI was less than that required for CADESI-03 (1.9 and 12.6 min, respectively), a highly significant difference (P < 0.001). CONCLUSION AND CLINICAL IMPORTANCE: The CADLI was found to be an effective measure of CAD lesion severity, strongly correlating with CADESI-03. The convenience of CADLI makes it suitable for use in both clinical research and practice.

Otic flushing.

Otic flushing has the potential to help a number of patients with ear disease. Because the diagnostic and therapeutic benefits of this procedure exceed its risks, veterinarians should offer otic flushing for patients with poorly responsive or chronic otitis externa.

Recognizing pyoderma: more difficult than it may seem.

Although bacterial pyoderma is among the most commonly encountered dermatologic conditions in dogs, some cases present diagnostic challenges even to experienced clinicians. This article presents several unusual manifestations of pyoderma, including bullous impetigo, superficial spreading pyoderma, mucocutaneous pyoderma, and post-grooming furunculosis. Conditions mimicking pyoderma, including juvenile cellulitis, immunomodulatory-responsive lymphocytic-plasmacytic pododermatitis, and pemphigus foliaceus are also described. Diagnostic techniques used for diagnosing and characterizing pyoderma are also discussed.