An itchy pet is a common reason for owners to bring their pet to the Vet. The medical term for itchiness is called 'pruritis'. Bacterial infections and parasite infestations (such as fleas or mites) are a common cause of pruritis in pets. However, did you know that in a small number of cases, itchiness can be caused by a food allergy?

Holly is an 8 year-old Maltese X who visited us in February. Holly's owner Erin explained that Holly had always been an 'itchy' dog. However, the scratching and licking had been particularly intense recently.

No lasagna for Holly!Erin fed Holly a home-cooked diet of cooked chicken, rice and pasta and vegetables. However, Holly had been fed a supermarket canned and dry food for a short period recently while Erin was on holidays. The recent flare-up of the skin seemed to coincide with the change of the diet. Erin had since resumed the home-cooked diet and the scratching and licking seemed less intense.

On examination, the skin appeared red and inflamed and slightly greasy. All the skin had the same appearance, that is it was not localised to a particular area of the body. There were no skin lesions to indicate a bacterial infection and there were no fleas present. Holly was on monthly flea prevention.

Our veterinarian suspected that Holly may have a food allergy. A food allergy can be diagnosed by feeding a special diet (Hills ZD Ultra or Royal Canin Hypoallergenic) exclusively for a minimum of 4-6 weeks. This is referred to as a food trial. It is important that the owner ONLY feeds the special diet. No treats or 'extras' are allowed.

Holly is happy and playful again after resolving her skin problemHolly was fed Royal Canin Hypoallergenic exclusively for 6 weeks. She was also prescribed a short period of anti-inflammatories to calm down the skin to help her feel more comfortable. Holly's skin improved significantly over the period of the food trial. She still scratched occasionally but there was no longer the intense scratching and licking seen previously.

The final step in the diagnosis is to 're-challenge' the food allergy. This involves re-introducing a protein (chicken, beef, cheese etc) to the diet, one protein at a time. If there is a noticeable flare-up to the skin, it can be assumed that there is an allergy to this particular protein.

Holly was re-challenged with chicken. Within days of re-introducing chicken to the diet, Holly began to scratch and itch again. However, the food allergy search continues because pets can be allergic to more than one protein.

Holly is now back on Royal Canin Hypoallergenic dry food. Once the skin has settled down again, Holly will be re-challenged with a different protein. Erin plans to try lamb next. It can be a long process but eventually Erin will be able to work out which foods are appropriate to include in Holly's diet.

Other related articles:

• Scratching or itchy skin - does it mean fleas? 
• Skin - the difference between canine and human
• Feeding your dog