protein allergies are very common. Generally speaking, a dog can be allergic to anything- chicken, beef, corn, wheat...so it's certainly possible!
FWIW benadryl won't do anything for food allergies. For environmental ones, it may or may not help (about 1/4 of the time it helps). Most dogs with environmental allergies don't improve much on benadryl so I wouldn't rule it out in your friend's case.
FWIW benadryl won't do anything for food allergies. For environmental ones, it may or may not help (about 1/4 of the time it helps). Most dogs with environmental allergies don't improve much on benadryl so I wouldn't rule it out in your friend's case.