Why does my Maltese smell musty after bathing? Is it a breed issue?

Maltese due have a predilection for getting a certain type of yeast infection in their skin, which will give that stinky, musty type of smell.

You are right that over-bathing can be harmful, because this can break down their natural defenses. However, in this case, these guys will need more frequent bathing with a medicated shampoo. You should get a medicated shampoo that is labeled for dogs. This can be purchased from pet stores or veterinary clinics.

Give them a bath with the medicated shampoo once every other day for two weeks, then once a week after that for a month. You should ensure that the shampoo is worked well into the skin and left for 15 minutes before rinsing. You should also make sure to wash their face, because this is a common source of the smell. They should start to smell better in two weeks. If you are not noticing a change by then, then it's best to take them to a vet for an evaluation, because they may need a prescription shampoo in order to clear this up.

Normally, you should not bathe more often than once a month with a shampoo labeled for dogs. You may consider doing the medicated bath once a month for these guys, since they seem to be predisposed to these yeast infections.

I hope that helps and this gets cleared-up soon.