Comparison of two shampoos as sole treatment for canine bacterial overgrowth syndrome

Two antibacterial shampoos for the treatment of canine bacterial overgrowth syndrome (BOGS) were compared in a prospective controlled clinical trial. Forty dogs with clinical signs (pruritus, erythema and excoriations without pustules and/or collarettes) and cytological findings compatible with bacterial overgrowth were treated twice weekly with 3 per cent chlorhexidine shampoo (3 per cent CHX) or 2.5 per cent benzoyl peroxide shampoo (2.5 per cent BPO) and evaluated every two weeks for up to six weeks until cytological cure. Pruritus, erythema, greasy seborrhoea, malodour, excoriations, secondary hair loss, lichenification, hyperpigmentation and lesion extent were each scored on a 0 to 3 severity scale and combined to calculate an aggregate score. Among the 34 dogs with good compliance to treatment, reduction of cocci counts of at least 90 per cent was recorded in 11 of 18 dogs after 3 per cent CHX and nine of 16 dogs after 2.5 per cent BPO, with no significant difference between the two products (P=0.98). Lesion score was significantly reduced in both groups (63.48 (34.45)) per cent with 3 per cent CHX v 54.45 (33.61) per cent with 2.5 per cent BPO, P=0.36) and time to cytological cure was not significantly different between groups (P=0.13), at the end of the treatment. In the present study, 3 per cent CHX and 2.5 per cent BPO were similarly effective in the treatment of canine BOGS.