Q:  I have a Standard Poodle who is 2 years old. I just rescued her about 5 weeks ago, and I have limited information regarding her past care and feeding. When I got her she had several larges patches where her hair was missing, and her hair was also missing around her eyes. I have had her spayed and my vet prescribed an allergen-free food thinking she may have a food allergy. She seems to be doing well on the diet as long as I keep her from eating anything else including treats. The hairless areas are looking much better, but I am wondering how long you think it should take for the hair to re-grow. Also, would you recommend doing allergy testing to isolate exactly what she is allergic to or should I just continue feeding her the prescribed diet?

A:  Congratulations on the new addition! Essentially right now you are doing a food trial which is the best means of detecting and controlling a food allergy as methods used to diagnose other types of allergies such as blood tests and intradermal testing (injecting a tiny amount of the suspected allergy into your dog to test your dog's response) are not very accurate in diagnosing food allergies.

A food trial consists of changing your dog’s food to either a limited ingredient food or a hypo-allergic food such as the one you are feeding your dog. During the food trial (and afterwards if the food used in the trial works), it is essential that you do not allow your dog to have ANY  flavor-containing chew, treat, toy, medication, or supplement. Symptoms such as itchiness and redness can take about 12 weeks to really abate. Re-growth of the hair will likely take longer – in fact, it may take up to a whole year to fully return.