Journal Scan: Shampoo as good as drugs in treating superficial pyoderma?

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Why they did it

The emergence of antibiotic-resistant strains of bacteria involved in the development of superficial pyoderma has led to increased interest in finding ways to treat this disease without the use of systemic medications. There are currently no studies that compare the use of topical antiseptics with systemic antibiotics in the treatment of canine superficial pyoderma.

What they did

Dogs were enrolled in the study if they had a clinical diagnosis of superficial pyoderma based on “the presence of one or more papules, pustules, epidermal collarettes or crusts, with detection of at least one neutrophil with intracytoplasmatic bacteria on cytological examination.” Dogs with deep pyoderma, yeast or ectoparasite infection and those with recent anti-inflammatory or antibacterial therapy were excluded. Specimens for culture and sensitivity testing were collected at the initial visit (day 1). A total pyoderma score (based on lesion severity and the number of intracellular bacteria) as well as a pruritus score were assigned at baseline and assessed at each visit. Dogs were re-evaluated on days 7, 28, and 56.

At the initial visit, dogs were randomized into two groups:

• Group T (n=31): treated for four weeks with 4% chlorhexidine digluconate shampoo twice weekly as well as 4% digluconate solution applied once daily on the days when not shampooed.

• Group S (n=20): treated with 25 mg/kg orally twice a day with amoxicillin/clavulanic acid.

Dogs with methicillin-resistant Staphylococcus pseudintermedius (MRSP) assigned to group S were reassigned to a nonrandomized group and treated with the topical therapy protocol and not included in the statistical analysis.

What they found

The researchers found S. pseudintermedius in the cultures of 48 dogs, eight of which were methicillin-resistant strains. While the total pyoderma score was higher among dogs in group S at baseline, there was no significant difference in this score between the two groups in response to therapy. Both groups did demonstrate a significant improvement in the total pyoderma score as well as improvement in the pruritus score.

The authors acknowledge that higher baseline pyoderma scores in group S may have overestimated the efficacy of therapy in group T.

Take-home message

The use of topical chlorhexidine shampoo appeared as effective as systemic antibiotic therapy for treating canine superficial pyoderma, even in cases of methicillin resistance. Further studies with a larger group of dogs are warranted.

Borio S, Colombo S, La Rosa G, et al. Effectiveness of a combined (4% chlorhexidine digluconate shampoo and solution) protocol in MRS and non-MRS canine superficial pyoderma: a randomized, blinded, antibiotic-controlled study. Vet Dermatol 2015;26:339-345.

Link to article: http://onlinelibrary.wiley.com/doi/10.1111/vde.12233/full