Epithelial or dandruff allergen for the diagnosis of dog allergy by RAST?

When used for screening by the RAST technique, dog epithelium provided too few positive results (29.2%) compared with dog dandruff (58.8%), cat epithelium (53.6%) and horse dandruff (52.2%). However, dog dandruff can provide an unexpectedly high incidence of positive RAST results (45.2%) in sera from patients with an allergic history to cat or horse, but not to dog. Dog dandruff allergens were found to cross-react with some cat or horse serum proteins in about 25% of such patients. We conclude that dog dandruff is preferable to epithelium for screening by the RAST technique, but if emotional issues involving a family pet arise then confirmation by a trial separation is likely to be more convincing than a provocation test with a possibly non-specific allergenic extract.