Investigations of the symptomatology and the significance of immediate skin test reactivity in canine atopic dermatitis.

Immediate skin test reactivity was determined with skin threshold concentrations of different allergen solutions in 208 dogs suspected of atopic dermatitis. Thirty-eight of the dogs (18.3 per cent) exhibited no reaction. Multisensitivity occurred in 59.1 per cent. House dust (39.4 per cent), human dandruff (39.9 per cent), dog dandruff (25.0 per cent), cat dandruff (29.8 per cent) and grasses (21.2 per cent) caused most of the positive reactions. The number of immediate skin reactions per dog was increased in those dogs that had had clinical signs for two to three years, as compared to dogs having had clinical signs for five or more years. Involvement of the extensor aspect of the carpal joint (41.2 per cent) and the flexor surface of the tarsal joint (30.6 per cent) was noticed only in dogs with positive immediate skin test reactivity. Together with the frequent occurrence of lichenification (84.1 per cent) this distribution pattern in dogs seems to mimic the signs of atopic dermatitis in man more closely than has been described previously.