Source: DVM 360
By: Jacqueline Gimmler, DVM, Jenise Daigle, DVM, DACVD
Classically, atopic dermatitis is thought to be caused by a genetic defect in the immune system, leading to a hypersensitivity to normal environmental allergens. Newer theories propose that genetic defects in skin lipids and proteins create a barrier defect that lets allergens into the body, stimulating an immune response. The study of skin barrier function in dogs is the subject of a lot of research, and measuring transepidermal water loss is commonly used to estimate barrier function. New topical treatments geared toward improving the skin barrier are emerging and may be useful additions to the classic atopic dermatitis treatment protocol.
NEW TOPICAL THERAPIES
Some new topical therapies have been developed with the goal of improving epidermal barrier function. The theory is that topically applying lipids to the skin stimulates it to produce its own lipids, leading to barrier repair. These therapies are different from supplementing fatty acids because they are administered directly onto the skin and because many of them provide ceramides, the most important lipid component of the skin barrier. It has been shown that the skin barrier cannot be disrupted unless ceramides are removed.
1. Allerderm Spot-On (Virbac Animal Health; $20 to $30 for a six-pack), a ceramide and fatty acid-containing liquid, is applied to the skin in a similar manner to monthly flea control products. The instructions for this product are to apply one pipette a week for four weeks and then one pipette a month for maintenance.
2. Dermoscent Essential 6 spot-on (Laboratoire De Dermo-Cosmetique Animale, Castres, France; $15 to $20 for a four-pack) contains essential oils and fatty acids. The instructions for this product are to apply one pipette a week for eight weeks and then one pipette every two weeks for maintenance. In a small study, seven atopic dogs were treated with this product for eight weeks and had their canine atopic dermatitis extent and severity index (CADESI) scores measured before and after treatment.9 They had statistically significant improvement (P = 0.0043) in severity of disease, though there was not a control group.
3.Sogeval Laboratories makes a line of products containing phytosphingosine, a precursor to ceramides (Figure 5). Douxo Seborrhea Shampoo (Sogeval Laboratories; $50 to $65 for a 25-pack) can be used one or two times a week along with the Douxo Seborrhea Micro-emulsion Spray (Sogeval Laboratories). Duoxo Seborrhea Spot-on (Sogeval Laboratories) can be used alone or in combination with the shampoo or spray and should be applied once weekly for four weeks and then twice monthly for maintenance.