Most regular dog shampoos smell nice. You wash your dog in the nice smelling shampoo and wash it off because it’s shampoo. But a bit stays on the coat and your dog smells good until the next day and then they smell again. Or they get wet and smell even more. Why?
Because they probably have seborrhea and a skin infection. A mixed bacterial and yeast infection which makes the skin and hair smell like old socks or a dog bed not washed often enough and may look like dandruff.
Seborrhea is the overproduction of the oils in the skin which end up on the hair coat. The skin makes too much oil in response to genetic factors or most commonly allergic dermatitis. The more oil and skin cells trapped on the coat the more food for bacteria and yeast and bingo, greasy smelly dog.
Treatment involves treating the infection, usually with antibacterial and anti-fungal shampoo designed for dogs with seborrhea and other symptomatic controls. Diagnosing and treating the underlying allergy is the best way to stop it coming back. No more smelly dog!