Rosanna Marsella, Luisa Cornegliani, Ibrahim Ozmen, Mary Bohannon, Kim Ahrens and Domenico Santoro
Introduction
Atopic dermatitis (cAD) is a common pruritic skin disease in dogs that requires chronic long-term management Canine AD results from a combination of genetic and environmental factors. One important aspect of this dis- ease is the efficiency of the skin barrier. Skin barrier defects have been demonstrated in cAD A defective skin barrier facilitates the penetration of allergens and ncreases the risk for allergic sensitization and thus sub- stantial interest exists in identifying safe therapies to repair the skin barrier with the final goal of improving clini- cal signs.
Skin barrier impairment has been linked, at least in part, to decreased cutaneous ceramide content Decrease in certain ceramides in lesional and nonlesional skin of atopic dogs has been linked to increased skin barrier per- meability Topical application of lipid emulsions contain- ing essential fatty acids (EFA) has also been shown to ameliorate skin barrier function and decrease the severity of clinical signs in dogs with AD. This type of therapy is considered useful to decrease the severity and fre- quency of allergic flares.
Pruritus is an important clinical sign of cAD thus topical therapy containing ingredients that could decrease pruri- tus would be very beneficial. Staphylococcal colonization is also common in AD and secondary infections are known to aggravate the disease. Interestingly, 18-beta glycyrrhetinic acid (GRA), a component of the liquorice root Glycyrrhiza spp., has been shown to have antipruritic properties in mice and an inhibitory effect on methi- cillin-resistant Staphylococcus aureus. These properties have stimulated interest in this ingredient as a potential topical preparation for the management of human AD. Several clinical trials have confirmed the beneficial effects of GRA in human AD as a safe alternative to the use of steroidal preparations and antibiotics.
The purpose of this study was to evaluate the efficacy of a topical lotion composed of blackcurrant oil (rich in alpha-linolenic acid and gamma-linolenic acid), ceramides and GRA, on clinical signs (skin lesions and pruritus) and skin barrier function in dogs with naturally occurring AD. The primary outcome assessed in this study was clinical efficacy as measured by pruritus scores and the effects on dermatitis severity and extent. Secondary outcomes were the noninvasive assessment of skin barrier function as measured by transepidermal water loss (TEWL) and global assessments (GA) by both investigator and owners over the course of 90 days.
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