Optimising Topical Therapy in the Dog

Topical (locally acting) therapy is important in the management of many dermatological conditions because the skin is readily accessible to medications. Several formulations are available for the prescribing veterinary surgeon and may include many active ingredients. The active ingredients penetrate the skin through the intercellular spaces (lipophilic molecules), through the epidermal cells (ion compounds) and above all through the hair follicles in animals, particularly for ionized molecules. Canine skin is often more sensitive than is human skin due to anatomical and physiological differences, including differences in the thickness of the stratum corneum, skin pH and hair follicle density which can facilitate cutaneous penetration of active ingredients. The use of shampoos will be emphasized in this paper; antiparasitic and auricular topical products are beyond its scope.