Epidermal dysplasia and Malassezia infection in two West Highland White Terrier siblings: an inherited skin disorder or reaction to severe Malasseziainfection?

Two 9-month-old West Highland White Terrier siblings were referred to our c linic with pruritus, alopecia and lichenification. Cytological examination of Scotch(TM) tape strippings revealed Malassezia organisms and cocci. Skin biopsy specimens showed epidermal dysplasia. Treatment included bathing wi th a 2% miconazole/chlorhexidine-containing shampoo, orally administered ke toconazole (5 mg kg-1, every 12 h) and cloxacillin (25 mg kg-1 every 8 h). Six weeks later, the dermal infection had resolved and there was hair regro wth. However, the dogs were still moderately pruritic. Intradermal allergy testing was positive for house dust mites, storage mites and Malassezia. Im munotherapy was initiated, and treatment with ketoconazole and cloxacillin was stopped. Skin biopsies, which were performed in both dogs 4 months afte r the first presentation, revealed mild superficial perivascular dermatitis . The remaining mild facial pruritus was easily controlled with topical tre atment. These two cases indicate that epidermal dysplasia might be an infla mmatory or hypersensitivity reaction to the Malassezia infection or a resul t of excessive self-trauma, rather than a congenital keratinization disorde r.