Mange is caused by mites, which are tiny arachnoid parasites. There are two types of mange found in dogs, demodectic, with is not contagious to humans and causes less severe symptoms, and sarcoptic mange, which is contagious to humans and causes more intense itching and hair loss. Mange occurs when these parasitic mites burrow into your dog's skin and take up residence in skin pores and hair follicles. Once embedded, they secrete a substance that forms a barrier protecting them inside your dog's skin. Topical medications to treat mites will only work if the medication can come in contact with the mites. Bathing your dog with medicated shampoo to open up pores and expose the mites, so you can treat them with topical medications and dips is required to get rid of these nasty little bugs. Bathing may also provide some relief from symptoms of mange, by removing scaliness and greasiness that accompanies mite infestation and by soothing irritated skin.