Preliminary evaluation of two bathing methods for the management of Malassezia overgrowth in dogs with atopic dermatitis.

BACKGROUND: Antifungal shampoos are widely used for canine Malassezia dermatitis. Few studies have evaluated effective bathing methods for atopic dogs with Malassezia overgrowth. OBJECTIVES: To evaluate the efficacy of an emollient bathing product (AFLOAT VET) and 2% miconazole/2% chlorhexidine shampoo (2% MIC/CHX) in atopic dogs, and to evaluate the influence on skin barrier function of both products in healthy dogs. ANIMALS: Sixteen atopic dogs with secondary Malassezia overgrowth and 11 healthy dogs. METHODS AND MATERIALS: This study was a randomized, single-blinded trial. The dogs were randomly treated with either emollient bathing or 2% MIC/CHX, twice weekly for four weeks. Clinical assessment used the Canine Atopic Dermatitis Extent and Severity Index, 4th iteration (CADESI-04), pruritus Visual Analog Scale (pVAS), and cytological evaluation of yeast numbers at Day (D)0, D14 and D28. Skin barrier function was determined by measuring transepidermal water loss (TEWL) after a single bathing procedure with each product in the healthy dogs. RESULTS: The pVAS scores and yeast counts were significantly reduced on D28 compared with D0 in both groups (P < 0.05). CADESI-04 was significantly decreased on D28 in the emollient bathing group (P = 0.003). There were no significant differences in each endpoint score between the groups. In healthy dogs, TEWL was significantly increased after bathing in both groups (P < 0.01). CONCLUSION: An emollient bathing product can be effective for Malassezia overgrowth in dogs with atopic dermatitis. Bathing with shampoo products might affect skin barrier function even when using an emollient product.