skin and ear

Question
My 4&3/4 yr old black lab has chronic ear problems, itchy, rashy, dandruffy skin.  He chews his paws, and has lost hair around his anus and mouth.  2 days ago, I changed his food to a lamb/rice mixture to see if it's alergies, and today he has not eaten and just threw up (it was bright yellow).  The last time I took him to our vet, we went thru months of medicines and lots of steroids. Am I on the right track - or does he need medical care?

Answer
IF he is chewing his paws and having ear problems, this may not be a food allergy entirely.  This may also be atopic dermatitis, which is very common in labs.  Steroids help environmental allergies, but not usually food allergies. Often there is a secondary bacterial or yeast infection that makes the dog more itchy.  If these things are not being treated, then ask your vet to address them.

Food trials are difficult.  To properly do this, select a food with only one protein source and a carbohydrate source (for example, venison and potato)...nothing else.  No treats, table food, flavored heartworm pills, or any other type of protein can be given.  This is done for 3 m onths to see if the dog's skin quiets down.  Then we re-intorduce one protein at a time to see if the dog reacts.  Only then we know which type of protein source to stay away from.