What skin problem is it suffering ? Is it loss of fur from any part of the body?, loss of hair all over the body? Do you see red rashes/pimples on the body? Does your dog itch constantly?
You can clean the infected area with betadine and then apply the wound with a good anti-fungal/bacterial ointment like Spectrazole. You should take your dog to the vet because on the basis of severity of the infection, he may administer some antibiotics.
This infection could be due to constant exposure to water/moisture to body. You may be giving excessive bathing to your dog all this summer. Dogs need bathing only once in the month, even in Summer. What they need regularly is daily brushing to keep the coat in healthy and clean state.
You also need to keep the diet right. You may be feeding too much grain based diet to your dog. Your dog needs protein in the form of chicken, egg, curd, fish. Don't feed packed dog foods which contain corn as part of ingredient. Corn is a cheap filler in dog food. You can feed supplements rich in fatty acids like Omega 6 and omega 3.
For tick/flea control, I recommend using anti-tick collars. They work all time on the body. Keep the tick/fleas at bay. If you do online shopping, you can buy it from this very site. If you need any further help, please feel free to talk.