If the itching is severe, your dog might eat, sleep, or play less because he feels so miserable. Other than scratching to relieve the itch, your dog will rub, lick, chew and bite different parts of his body (e. g. , face, armpits, feet). Skin allergies can sometimes lead to ear infections, so your dog might start shaking his head because his ears feel itchy. This head shaking can lead to the development of a hematoma (large mass of blood) on his ear. Clinical signs of skin allergies usually start appearing when a dog is 6 months to 3 years old. [4] X Research source
His skin may also start developing scales. The scratching can lead to secondary bacterial or yeast infections on the skin, which would make the skin smell bad. Small red dots, called macules, can form on your dog’s skin because of all of the scratching. [7] X Research source
Treatments for FAD include medicated flea and tick shampoos, flea and tick sprays, and topical flea preventatives. Use the spray in a well-ventilated area. [9] X Research source Use these products according to the product label instructions, as well as your veterinarian’s instructions. You can also get rid of fleas by vacuuming your home more frequently and washing your dog’s bedding hot water. If your dog is still miserable and itchy after being treated for fleas, then FAD can be ruled out. Interestingly, fleas can trigger development of CAD. [10] X Research source
If your veterinarian does not see mites in the skin scraping, he or she will likely rule out mange. Even if no mites are present, the skin scraping may reveal bacteria or yeast, indicating a secondary skin infection caused by the scratching. Your veterinarian will treat your dog for these infections.
A food elimination trial involves feeding your dog only the new food for 8 to 12 weeks to see if his allergy symptoms go away, then re-challenging him with his old food to see if the symptoms come back. [12] X Research source If your dog’s itchiness persists throughout the food elimination trial, your veterinarian will likely rule out a food allergy. Hypoallergenic foods are available through your veterinarian.
Blood testing is not as accurate as intradermal skin testing. Also, results can take up to 2 weeks. [14] X Research source
Your dog will be sedated for the procedure. [16] X Research source After the injection, your veterinarian will monitor the skin reaction for 15 to 20 minutes and grade it according to the redness and size of the injection site. Swelling at the injection site indicates a possible allergy. Intradermal skin testing is more accurate than blood testing, but false results can occur for a number of reasons, including bacterial or fungal contamination of the allergen, too little antigen injected, and poor injection technique.
