Clinical and microscopic features of generalized discoid lupus erythematosus in dogs (10 cases).

BACKGROUND: Generalized discoid lupus erythematosus (GDLE) is a newly recognized canine variant of chronic cutaneous lupus erythematosus (CLE) that is not well characterized. HYPOTHESIS/OBJECTIVES: We report herein the signalment, clinical signs, treatment outcome, histopathology and immunological findings of 10 dogs with GDLE. METHODS: Inclusion criteria were: (i) a >3 month history of generalized skin lesions indicating a chronic or recurrent nature; (ii) skin lesions resembling those of human GDLE; (iii) histopathology of CLE (lymphocyte-rich interface dermatitis). Direct immunofluorescence (IF) and antinuclear antibody serology were investigated whenever possible. RESULTS: Various breeds were affected in their mid- to late adulthood. Selection criteria of generalized multifocal, annular ("discoid") to polycyclic plaques with pigment changes, erythematous margin, adherent scaling, follicular plugging and central alopecia were shown in all dogs. In nine dogs, plaques contained mild to moderate central scarring with depigmentation and/or hyperpigmentation. There were no dogs in which the disease progressed to systemic lupus erythematosus within a median follow-up of 2.5 years. Per inclusion criteria, interface dermatitis occurred with basement membrane zone (BMZ) thickening, suprabasal apoptosis and/or dermal fibrosis in some dogs. Infundibular interface folliculitis was common; it sometimes transitioned to mural folliculitis in lower follicle segments, and occurred with follicular and sebaceous gland atrophy. The direct IF revealed patchy deposition of immunoglobulin IgG and IgM at the BMZ. Lesions responded to a variety of treatments, including ciclosporin, hydroxychloroquine, topical tacrolimus and tetracycline/niacinamide. Relapses were common after medications were tapered. CONCLUSIONS AND CLINICAL IMPORTANCE: These observations support the existence of a canine homologue of human GDLE.

A pilot study comparing in vitro efficacy of topical preparations against veterinary pathogens.

BACKGROUND: Topical antimicrobial agents are important for the management of cutaneous infections. For topical antimicrobial agents, in vitro efficacy data are limited. OBJECTIVES: To determine and compare the minimum bactericidal/fungicidal concentrations (MBCs/MFCs) of several topical antimicrobial agents against veterinary pathogens. MATERIALS AND METHODS: Two chlorhexidine, two oxychlorine based products (NaOCl & HOCl) lime sulfur (LS), manuka honey (MH) and hydrocortisone aceponate (HCA) were tested against American Type Culture Collection (ATCC) and clinical isolates: meticillin susceptible and resistant Staphylococcus pseudintermedius (MSSP), qac A/B carrying MSSP, antimicrobial susceptible and extended spectrum beta-lactamase producing Escherichia coli, multidrug-resistant Pseudomonas aeruginosa and Malassezia pachydermatis. The MBCs/MFCs were measured, where available, using a broth microdilution method; isolates were incubated for 3 and 10 min. RESULTS: Chlorhexidine and isopropyl alcohol (Chl(1) ) showed significantly lower MBCs (0.46 mg/L -937.50 mg/L, P = 0.027) compared to chlorhexidine and climbazole (Chl², 58.59 mg/L-1875 mg/L). NaOCl and HOCl showed excellent antimicrobial activity with HOCl having significantly lower MBCs compared to NaOCl (0.03 mg/L-1.72 mg/L and 0.03 mg/L-1.95 mg/L, respectively, P = 0.042). The detectable MBCs for LS and HCA were high, being close to the starting concentration (5,000 mg/L and 146 mg/L, respectively). The MBC/MFC for MH was not detectable. Amongst all test products there was no significant effect of contact time or isolate resistance status. CONCLUSIONS AND CLINICAL IMPORTANCE: Chlorhexidine, NaOCl and HOCl demonstrated low MBCs against tested organisms, suggesting potential in vivo efficacy. The selection of an appropriate antimicrobial agent, however, cannot be based exclusively upon MBC/MFC data; other factors should be considered.

Canine atopic dermatitis - what have we learned?

Canine atopic dermatitis is a complex multifactorial disease. Here, Tim Nuttall, Maarja Uri and Richard Halliwell, representing three generations of veterinary dermatologists, describe the research underpinning our understanding of the condition and highlight its relevance to clinical practice.