Pet owners often turn to professional groomers for help when their dogs are scratching excessively. Often they suspect fleas or dry skin as the reason for itchy, irritated skin, and assume that a bath or deep conditioning will remedy the problem.

But another reason may be the culprit. Just as humans experience food allergies, so too do about 10% of dogs. Only flea bite allergies and environmental allergies are more common in canines than allergies to food.

The most common signs of food allergy are inflamed, itchy skin. The dog's face, feet, ears, armpits and groin are the most likely to become inflamed. Other common symptoms include recurrent ear infections, hot spots, and excessive scratching, which can lead to secondary skin infections. Some dogs may experience vomiting and diarrhea as well.

If you or your groomer suspect a food allergy, it's important to consult your veterinarian, because there are diseases and other problems whose symptoms may mimic those of allergies.

Diagnosing food allergies can be challenging. And, perhaps surprisingly, dogs can develop allergies to those foods that are most frequently fed, such as beef, dairy, chicken, corn, wheat and soy.

Working with your vet, you should begin the process of identifying whether or not the allergy is to food or to other factors. The best way is to begin a food trial. A restrictive diet trial will replace your pet's normal diet with a diet containing proteins and carbohydrates completely novel to your pet.

For many years, lamb and rice was recommended for food allergy testing. However they are no longer considered a safe novel food source, since most companies now add other ingredients like corn, chicken and beef to their lamb and rice formulas. Instead, veterinarians turn to more exotic sources of protein such as fish, rabbit, venison and carbohydrates such as potatoes and yams, said Dr. Kinga Gortel of the University of Illinois College of Veterinary Medicine Teaching Hospital. There are commercial products on the market, or you can prepare the food at home.

You should keep your dog on this new diet for 12 weeks, and be careful to feed only that. This means no treats, table scraps, or bones. If the symptoms disappear, you can then re-challenge your pet's system by reintroducing his original food, which is called provocative testing. If the symptoms reappear, the diagnosis of a food allergy is confirmed.

Once that diagnosis is made, you should return to the special diet. If you prepare the foods at home, you can then reintroduce ingredients one at a time, to determine which foods caused the allergic reaction. By testing specific foods, you can eventually design a diet that is free of the offending foods.

Your professional groomer, whose daily job it is to care for and inspect animals' coats, can be a resource in helping to identify possible food allergies. If your pet suffers from itchy, irritated skin, seek help. You don't want your best friend to suffer unnecessarily.