%0 Journal Article %T Pilot Study to Evaluate the Effect of Topical Dimethicone on Clinical Signs and Skin Barrier Function in Dogs with Naturally Occurring Atopic Dermatitis %A C. Pellicoro %A R. Marsella %A K. Ahrens %J Veterinary Medicine International %D 2013 %I Hindawi Publishing Corporation %R 10.1155/2013/239186 %X This study investigated the effects of a skin protectant solution (dimethicone 2%) on clinical signs and skin barrier function in canine atopic dermatitis (AD). Eighteen dogs with AD were randomly divided into two groups, one received dimethicone and the other received the vehicle (cyclomethicone) on selected areas (pinnae, groin, and axillae) daily for 4 weeks. Owners and investigators were blinded regarding group allocation. Clinical efficacy was evaluated using a scoring system and skin barrier by measuring the transepidermal water loss. Twelve dogs completed the study (50% drop rate in the vehicle and 20% in the dimethicone). For clinical signs, analysis of variance showed an effect of time ( ; day 0 day 28) and region (axillae groin pinnae) but no effect of group or group กม time interaction. For transepidermal water loss, analysis of variance showed only a main effect of region (axillae pinnae groin). Pearson found no correlation between transepidermal water loss and clinical scores. In this pilot study dimethicone had no significant effect on clinical signs and transepidermal water loss in canine atopic dermatitis. 1. Introduction Atopic diseases (asthma, allergic rhinitis, and atopic dermatitis) have been reported to be increasing commonly in humans, especially in developed countries [1]. Although there is a genetic predisposition to the development of these diseases, the rapid rise in incidence is suspected to be caused by environmental factors rather than purely by genetic factors. Environmental factors that could play an important role include the increased exposure to agents that are able to disrupt the skin barrier such as the daily use of harsh soaps and the increased exposure to dust mites, which have proteolytic enzymes that can aggravate barrier. Numerous similarities exist between canine atopic dermatitis (CAD) and its human counterpart [2, 3], and many of the same environmental factors associated with the increasing incidence of human AD are found in the environment of dogs. Interestingly, a similar increase in the incidence of AD has been reported also in dogs [4]. In recent years, abnormal barrier function has received growing attention in the pathogenesis of AD [5, 6]. In humans with AD it has been demonstrated that skin barrier impairment is linked to both genetic mutations [7, 8] and inflammation [9]. It is hypothesized that the disturbed skin barrier allows increased penetration of environmental allergens into the skin; this promotes a T helper 2 shift that further aggravates skin barrier [10]. Much less is known in veterinary %U http://www.hindawi.com/journals/vmi/2013/239186/