Final answer:
Approximately 25% of Canine atopic dermatitis cases have no detectable allergen-specific IgE.
Step-by-step explanation:
Canine atopic dermatitis is an allergic skin disease in dogs, characterized by itching, redness, and inflammation of the skin as a response to allergens. In some cases, allergen-specific IgE antibodies can be detected in the blood, indicating an immune response to a particular allergen. However, not all cases of Canine atopic dermatitis have detectable allergen-specific IgE. Studies have shown that approximately 25% of Canine atopic dermatitis cases have no detectable allergen-specific IgE.