Vet360 Issue 5 Volume 2 | Page 24

ACCREDITED CPD ACCREDITED CPD • • persistence on the skin, but should not be used repeatedly for generalized skin problems due to its irritant and staining properties. Benzoyl peroxide: It is metabolised in the skin to benzoic acid. Much of its microbicidal activity derives from the lowered skin pH which disrupts microbial cell membranes. It is also an oxidizing agent, which releases nascent oxygen into the skin and produces a series of chemical reactions resulting in permeability changes and rupture of bacterial membranes. It has an excellent prophylactic effect and its follicular flushing, keratolytic degreasing and comedolytic activity are additional benefits. It is generally used in concentrations of 2 to 3%, which are well tolerated, but irritation can occur at higher concentrations (erythema, pruritus and pain). Quaternary ammonium compounds: They are surface acting agents. They have less effect and are only useful for limited bacterial involvement. They have no residual effect and have to be applied often for good effect. Keratomodulating shampoos These shampoos are indicated in cases with allergy induced keratoseborrhoeic changes. Keratomodulating agents include: • Salicylic acid (0, 5 – 2%) is keratolytic. It causes a reduction in skin pH, which leads to increased hydration of keratin. These actions help to soften the corneal layer. It acts synergistically with sulphur and is often present in small quantities in shampoos. • Sulphur (0, 5% - 2 %) is mildly keratolytic (forms hydrogen sulphide in the stratum corneum), keratoplastic (has a direct cytostatic effect) and has numerous anti-seborrheic effects. Topical lipids • Topical lipids have been used with success in improving the epidermal barrier in human atopic dermatitis. • There are a few published studies in the veterinary literature that have documented the effects of topical fatty acids on the barrier function in dogs. In one study the topical application of either a fatty acid containing spot-on (applied weekly) or spray (applied daily) improved both the lesions and pruritus in dogs with CAD. Another study showed that the spot-on formulation applied weekly for 8 weeks was beneficial in alleviating the clinical signs of both mild and severe cases of CAD. • A study by Piekutowska and Pin demonstrated an increase in epidermal lamellar lipids. This suggested that treatment with topical lipids stimulated the production and secretion of endogenous stratum corneum lipids, contributing to the formation of an improved epidermal barrier. • Topical lipids are more effective in restoring the • hydrolipidic film faster when compared to oral EFAs. Topical lipids also moderate sebaceous gland activity and sebum production, rebalance dry or oily coat and skin, are skin barrier enhancing and reduce TEWL for optimal skin hydration. Topical sprays: • A steroid-free topical spray has been developed for the symptomatic treatment of CAD. It has 100% natural active ingredients which have a synergetic efficacy and does not have any side effect of steroids. The spray is soothing, reduces skin inflammation, regenerates and repairs the epidermal barrier, decreases TEWL and has antimicrobial properties. • A corticosteroid spray that is not absorbed systemically is also available. Other topical treatments: • Topical glucocorticoids are useful in Veterinary Dermatology. They are the sole ingredient or part of combination formulations with antimicrobial and other agents and are useful for localised lesions. Tachyphylaxis, atrophy and microbial infections can occur in cases of overuse. • Immunomodulators: Tacrolimus, a calcineurin inhibitor has been shown to be effective in the treatment of localized lesions of CAD. • Antibiotics: formulations containing fusidic acid and mupiro