There are many types and causes for skin disorders. I would speak to my vet, some recommendations might include changes to diet, special shampoo, or medication.
The first thing you should do is take your pet to a vet. The vet will be able to run tests on your pet and hopefully be able to tell you have to alleviate the problem.
Your boxer might have a food allergy. Try feeding it different kinds of high quality food with different ingredients. Choose a food with no grain, because that is most likely what the dog is allergic to.
