ref: allergies
My boxer Ashley had skin problems when she was a puppy. Had to use a sterile type shampoo on her every three days until she was over 6 months. Also later found out can only use certain shampoos on her, oatmeal or fruit based, otherwise she breaks out in bumps all over. Then a couple weeks ago my male Noah got into something because his whole face puffed out, then within days bumps were all over his body. Vet said anything could really of caused it, maybe something he got into, because we didnt find anything showing he was bit by something. They gave him a steroid shot and told me if it did not go down in a couple days to use the benadryl. Also Ashleys face will get swollen once in awhile and they had given me some anahistamines to give her, and it goes down right away. Also if your boxer ever gets bumps under their chin, it could be because they are allergic to their bowls (if they plastic) and you'll have to use stainless steel ones. I was told that boxers can have allergies and sensitive skin problems, but I suppose all kinds of dogs can.