I had something similar last winter in two of my goats. Tried lots of things, including the vet looking at it, but nothing worked.
Used Eprinex (a pour on cattle wormer) which worked fantastically well on both animals, cleared it up completely. It always tends to be worse in winter when they are indoors more because the weather is worse. My female wasn't as bad initially because she had free access to range outside until January, and then once she moved into the big goat shed it kicked in.