The study of canine atopic dermatitis involving the isolation of dogs.

Twenty-seven pruritic dogs were used in this study. When a hypoallergenic diet was fed to these 27 dogs for six weeks, none of the dogs showed improvement of the pruritus. These dogs had a history and clinical signs of atopic dermatitis (AD) as defined by Prelaud's diagnostic criteria. Subsequently, the 27 dogs were isolated for observation for two weeks in the hospital. In the isolation room in the veterinary clinic, cages and tableware were all stainless steel, and carpet was not used. A hypoallergenic diet was continuously fed to the 27 dogs for two weeks, during which time they were kept in the isolation room. PVAS (Pruritus Visual Analog Scale) was performed prior to starting the isolation, at the start of the study and 2 weeks after starting the isolation. In 17 dogs (63%) the pruritus improved in the isolation room. A statistically significant reduction (p < 0.01) of PLS (Pruritus liners score) was recorded 2 weeks after isolation. It was hypothesized that the 17 dogs whose pruritus improved in the isolation room had AD caused by an environmental antigen that was not present in the isolation room. Pruritus of the remaining 10 dogs (37%) did not improve. For 6/10 dogs, the intradermal allergy testing was positive for an environmental antigen. For 4/10 dogs, the intradermal allergy testing was negative for all environmental antigens. Dogs for which sensitivity to an environmental antigen was not identified were thought to have atopic-like dermatitis.