Dogs hypersensitive to house dust mite.

Active intradermal skin reaction, respiratory resistance and respiratory patterns were examined in five dogs after intradermal injection or inhalation of house dust mite (Dermatophagoides farinae) extract and the results obtained were as follows: 1. Three out of the five dogs exhibited positive skin reactions against house dust mite extract solution at concentrations of 0.1 micrograms/ml to 10 micrograms/ml. 2. Inhalation of mite extract at a concentration of 1 mg/ml by the dogs that had positive skin reactions produced a marked increase in respiratory resistance and changes in spirogram. These results suggest that the dogs that exhibited positive skin reactions were spontaneously sensitized to D. farinae.