Eleven perennially affected atopic dogs which had previously responded poorly to dietary supplementation with a combination of evening primrose oil and fish oil were studied to determine whether a concentrated essential fatty acid supplement containing gammalinolenic acid and eicosapentaenoic acid would reduce their prednisolone requirements. The prednisolone dose required for satisfactory control of the dogs' clinical signs was reduced in eight of the 11 cases when assessed after 12 weeks of supplementation, but there were no significant differences in mean clinical scores during the same period. The mean plasma phospholipid linoleic acid concentrations after eight and 12 weeks of supplementation were significantly lower than the initial mean value but there were no significant differences in the mean plasma phospholipid concentrations of dihomogammalinolenic acid, arachidonic acid and eicosapentaenoic acid.

The thickness of, and number of cell layers in, the stratum corneum and the living epidermis were determined on frozen sections of washed and unwashed skin from normal and atopic individuals of both sexes. The stratum corneum of atopic patients was thinner and had fewer layers of dead cells and intercellular lipid than normal, although the living epidermis was thicker. Regular washing with soap and water had no appreciable effect on the dimensions of the living epidermis of either group but caused a reduction in the number of cell layers and the amount of sudanophilic material in the stratum corneum of both. In atopic patients little surface lipid remained, suggesting that washing with soap and water may be detrimental to the barrier function of the stratum corneum in such patients.

Thirty-five dogs with non-seasonal atopic dermatitis were used in a double-blind, placebo-controlled crossover study of the effects of evening primrose (Oenothera biennis) oil. There was a significant treatment effect (P less than 0.05) on erythema. An analysis of the changes in plasma phospholipid levels of essential fatty acids revealed a significant (P less than 0.05) rise in linoleic acid concentration above that in the placebo group. Arachidonic acid levels in the treated group increased significantly (P less than 0.005) in the first phase and also in the second phase (P less than 0.05). In the second phase the levels of arachidonic acid in the active and placebo groups differed significantly (P less than 0.05) and there was a significant treatment effect (P less than 0.05).

The concentration of immunoglobulins in faecal extracts was investigated as a method of assessing the production of immunoglobulins by the gut mucosa of 137 dogs. There were significant correlations between the concentrations in faecal extracts and the concentrations produced in duodenal organ cultures. Seventy-six German shepherd dogs had significantly lower median immunoglobulin A (IgA) concentrations in their faecal extracts than 63 controls of various breeds. Sixteen of the German shepherd dogs had IgA concentrations below the 95 per cent confidence limit of the control population and six had no demonstrable faecal IgA. The faecal concentrations of immunoglobulin G and albumin were significantly higher in the German shepherd dogs than in the controls, but their immunoglobulin M concentrations were similar.

No abstract