A staph infection generally appears when your dog has been to the vet for a procedure. It could be this option if your dog has undergone surgery recently in that area. Bad needles can also lead to infections. Surgery does not have to occur in the area for a staph infection to be the issue, though most often the infection begins at the surgical stage.
If it is not a staph infection it could be a skin problem. Various dog breeds are known for their sensitive skin. This is why giving a dog a bath should be done on a schedule because you may find the soap and water creates issues if you wash them too frequently. If the issue is a simple skin infection due to allergy or sensitive skin there are a couple of ways for it to be treated. You may be able to purchase a cream or ointment from your vet to help clear up the issues.
Whether the ointment is purchased through the vet, you still need to go visit the vet. They will diagnose the issue of the red spots. The vet will then be able to give you suggestions in how to clear up the issue. Most pet stores will have a variety of creams and other dog related over the counter options too. You may discover the pet store has what you need, once you have a diagnosis of the issue your dog has, but you must get a diagnosis from a professional first.