Dogs diagnosed with allergic dermatitis or atopy can either be skin tested (by a veterinary dermatologist) or blood tested to determine what they are allergic to. The blood test will test for allergens (plant pollens, dust mites, mold spores) to which the dog is hypersensitive/over-reactive. Once the allergens are determined a desensitizing vaccine (allergy shot) can be made. Most dogs (60-80%) will respond to their vaccine with less itching and fewer skin or ear infections. Improvement may take several months but vaccine amount and frequency tend to decrease over time.
Please ask about this service if you have an itchy dog.