Atopic dermatitis in the dog is a common pruritic inflammatory skin disease which is due to sensitisation to environmental allergens.
Diagnosis is based on thorough evaluation of the history, the presence of typical clinical symptoms, and exclusion of other differential diagnoses. The intradermal skin test is a further diagnostic tool which is regarded as gold standard in veterinary medicine. This test is usually carried out by veterinary dermatologists who possess the necessary equipment and experience to perform and interpret the test.
The detection of allergen specific antibodies from the patient¿s serum is a possible alternative to intradermal testing.
In the present study the results of the intradermal skin test of 44 possible atopic dogs were compared to the results of the ¿Allergoset® - Canine IgE INDOOR und OUTDOOR¿ (Fa. INTEX Pharmazeutika AG), an immunoblot ¿ assay based on a polyclonal ELISA system for the detection of allergenspecific IgE in the patient¿s blood. Additionally the clinical parameters of the patients were evaluated.
The intradermal skin test only gave positive reactions to indoor allergens. Seventyeight percent of the dogs reacted to Tyrophagus putrescentiae, 76 % to Acarus siro and 70 % to Dermatophagoides farinae.
In the ELISA a positive reaction to one outdoor allergen was also detected in three dogs. Five percent of the dogs reacted to Tyrophagus putrescentiae and Acarus siro, respectively and 73 % to Dermatophagoides farinae. The ELISA had a sensitivity of 0 % to 90 % and a specificity of 73 % to 100 % for the allergens tested. The relative error was up to 73 %.
The average age of onset of pruritus of the evaluated dogs was 1,9 years. The symptoms were nonseasonal in 79,5 % of the dogs. Generalised pruritus was evident in 52,3 % of the dogs, 72 % showed pruritus in the head region, 77 % at the paws and 66 % at the ventral body site. A secondary pyoderma was diagnosed in 64 % of the patients and Malassezia
- dermatitis in 5 %. Otitis externa was present in 30 %.
Due to wide variations of the results for the single allergens in the ELISA this test cannot be regarded as replacement for the intradermal test.
atopic dermatitis / intradermal test / ELISA / polyclonal AB / dog