Essential Fatty Acids and the Cat

Skin as a marker of general feline health: Cutaneous manifestations of systemic disease

Practical relevance: Although most skin lesions occur due to diseases primarily affecting the skin, some reflect important systemic diseases. Such lesions may relate directly to the systemic disease, or may occur due to secondary skin diseases that develop because of immunosuppression. Early recognition of skin changes as a marker of systemic disease will maximise patient outcomes. Clinical challenges: In older or clearly debilitated cats presenting with skin disease, the potential for underlying systemic disease is often readily apparent. Similarly, cats presenting with severe ulcerative or multifocal nodular skin lesions, or with concurrent signs of systemic illness, will more instinctively prompt systemic evaluation. More challenging is the cat presenting with alopecic, scaling, erythemic and/or mildly crusted skin disease, with or without pruritus; hypersensitivities and infectious dermatoses are the most common considerations, but occasionally systemic disease underlies the skin changes. Knowing when screening laboratory testing, body imaging or other systemic diagnostics are indicated is not always straightforward. Evidence base: This article reviews cutaneous presentations of systemic diseases reported in the veterinary literature, and discusses important differential diagnoses. The author draws on clinical experience, published data on disease prevalence and case evaluations, and expert opinions on approach to common systemic problems to provide guidance on when investigation for underlying systemic disease is most appropriate.

Conjugated linoleic acid and black currant seed oil in the treatment of canine atopic dermatitis: A preliminary report

Although conjugated linoleic acid (CLA) shows inhibitory effects on histamine release, eicosanoid production and pruritus in laboratory rodents, its use in canine atopic dermatitis (AD) has not been reported. The aims of this study were to assess the efficacy of CLA, black currant seed oil (BSO) or a combination of both, compared to placebo, in dogs with AD and to evaluate any changes in fatty acid metabolism with these treatments. Twenty-four dogs with AD were randomly allocated to four groups, and were treated orally each day for two months with either 1 mL/10 kg CLA (80% purity), 1 mL/10 kg pure BSO, 1 mL/10 kg CLA+1 mL/10 kg BSO, or 1 mL/10 kg sugar syrup (placebo). Serum was obtained on days 0, 30 and 60 for analysis of CLA metabolites, linoleic acid (LA), gamma-linolenic acid (GLA), dihomo-gamma-linolenic acid (DGLA) and arachidonic acid (AA). At the same time point, the owners were asked to assess pruritus and the veterinarians evaluated any skin lesions present. Although the best clinical results occurred with BSO treatment alone, improvement of clinical signs and pruritus was not significant with any of the treatments. Serum levels of GLA and DGLA significantly increased in BSO-treated dogs, but not in the CLA+BSO group. CLA at the dosage used in this study was not efficacious in treating canine AD, whereas BSO may help some dogs with AD, although further studies are necessary before this can be recommended as a treatment.

Diet and skin disease in dogs and cats

Dietary factors have a major role in the maintenance of healthy coat and skin, and are significant in the etiology and therapy of certain skin diseases. Nutritional deficiencies are now uncommon as a result of the widespread feeding of complete and balanced pet foods. Deficiencies of (n-6) polyunsaturated fatty acids, zinc and vitamins, however, do arise in certain animal- or product-related instances. Supraphysiologic doses of vitamin A have been used in the management of vitamin A-responsive dermatosis in Cocker spaniels; other keratinization defects and seborrheic conditions may respond to retinoid therapy. Much interest has been paid to the therapeutic value of polyunsaturated fatty acid supplements in the management of dermatologic conditions associated with hypersensitivity reactions or keratinization defects. These studies have generally yielded disappointing results, which may reflect shortcomings in the design of some trials. Nevertheless, a placebo-controlled, double-blind, cross-over study has demonstrated a clear benefit of high dose (n-3) fatty acids in the management of pruritic skin disease. There is also preliminary experimental evidence that specific dietary (n-6):(n-3) fatty ratios are useful in the dietary management of inflammatory diseases. Although results of controlled clinical trials are awaited, the argument exists that it is the absolute amount of (n-3) fatty acid intake rather than ratio that is responsible for potential health benefits.