Jaybay is spot on. If they are annoying the dog, they should be removed to prevent infection. Also, if your dog is predisposed to picking at these, you will need to get the fancy "collar" (lampshade) to keep your dog from picking at the spots after they are removed.
Any wound that is constantly opened and reopened is going to eventually get infected. The guideline my vet uses for these growths is to leave them alone - unless the dog keeps biting them and making them bleed. In that case, they need to be removed.