How much does skin barrier count for allergic dermatitis improvement?

Abstract

Background Allergic dermatitis is a genetic-based skin condition affecting an increasing number of dogs. A more efficient treatment approach is often multimodal, including a special focus on skin barrier condition, from which many pruritic triggers depend as well as common complications. Aim: To evaluate the specific role of skin barrier-directed reestablishing treatment in allergic dermatitis clinical improvement. Method Five dogs with allergic dermatitis were selected from an allergy outpatient consultation. Owners’ informed consent was obtained upon approval by an ethics committee. Patients were subjected to clinical work up including Canine Atopic Dermatitis Extent and Severity Index 4 (CADESI-4) and specific diagnosis for atopy and/or food allergy, including intradermal testing (IDT). Skin biopsies were performed from a non-infected inflamed and adjacent non-affected area, and conserved in 4% buffered formaldehyde. Follow up lasted for 2-3 months, applying avoidance measures directed to the implicated allergen sources and treating with a phytosphingosine-containing shampoo/lotion, according to the manufacturer’s directions. Reassessment was done each 10-15 days with CADESI-4 and further IDT and skin biopsies performed at the end. Skin samples were histologically processed including staining for mastocytes and collagen fibers. Thickness of the non-keratinized epidermal layer and stratum corneum as well this lamina organization (scored 1-5), mast cell density and integrity, and collagen density in the dermal layer were assessed. Normal (N) and lesion (L) data, before and after treatment, were compared. Results Three patients showed evident clinical improvement, 1 moderately and 1 not (10-19, 3 and 1 respectively decrease in CADESI-4). IDT results did not differ. Non-keratinized epidermal layer and stratum corneum thickness ranged respectively 12/4 (N) to 330/300 μm (L) before treatment and 10/4 (N) to 120/120 μm (L) after treatment. Lamina cornea organization tended to increase with treatment, with no clear change in collagen fibers. Mast cell density improved in the recovered patients with 15.2% drop and integrity increased 22.8%. Conclusion Skin barrier-directed reestablishing treatment in allergic dermatitis allows for effective and significant clinical improvement, even as single choice treatment, and therefore should be considered as a non-side-effect treatment, especially when a curative immunological approach is not possible or ineffective.