The boxer side has an inherited condition called Atopy, which is a fancy way of saying allergy due to inhalation. It is usually seasonal, but doesn't have to be. You might consider treating with Benedryl 1-2 mg/lb. If given at night a side effect is a snoring puppy dog.

Ask your Vet for Panalog. Besides having an antibiotic, and a cortisteroid, it's best property (and worst) is that it's oil based. Quite a bit will soak into the skin before the dog can lick it off. So the trick is to rub it on, and take puppy for a walk. Else the dog is liable to rub all over your carpet with it.

If the Benedryl doesn't do the trick pursue getting Hydrozyzine a precription anti-histamine from the Vet, and ask about including a short term treatment with Prednisone.

If the above doesn't work, then ask for a referral to a doggy dermatologist.