Canine models of atopic dermatitis: a useful tool with untapped potential.

Animal models have contributed greatly to the expansion of knowledge in the field of atopic dermatitis (AD). Some species, such as the dog, naturally and commonly develop a pruritic dermatitis that is clinically and immunologically extremely similar to human AD. Recently, canine models of AD have been validated. In one of these models (Beagles), AD can be reliably reproduced upon allergen challenge, providing a tool with which to study effectively how AD is affected by allergen exposure. Interestingly, decreased epidermal filaggrin expression and disturbed extrusion of lamellar bodies by keratinocytes are present in these dogs, as well as increased transepidermal water loss, particularly in sites characteristically affected by AD. Owing to the remarkable similarity with the human disease, these dog models not only can help answer questions relative to the pathogenesis of the disease but also can be used as tools for rapid screening of drugs with potential clinical application, including those aimed at restoring epidermal barrier dysfunction.