Cross-allergenicity between extracts of hair from different dog breeds and cat fur

Skin tests and RAST determinations with breed-specific dog allergen extracts and a cat allergen preparation were made on forty-four atopic patients divided into three groups. Group 1 were twenty dog-owning atopic patients without clinical signs of dog sensitivity, Group 2 contained twenty-one patients with a clinical history that suggested allergy to dogs, and Group 3 contained ten atopic patients who were sensitive to cats. In neither the in vivo nor the in vitro tests was there any evidence for dog breed specificity, nor was dog albumin found to be a major allergen in the population studied, though a few individuals showed strong RAST activity to albumin. Furthermore, a cat fur extract inhibited the reaction between dog hair and anti-dog serum, and a dog hair extract inhibited the reaction between cat fur extract and anti-cat serum.