I've had yeast, AND eczema. I used Dr. Newman's APNO (all purpose nipple ointment, which contains hydrocortisone among other things), and that kept it in check. As soon as I stopped using it, I would get flaky and red, and always got a split in the skin in the base of my nipple. Ouch!
I did become concerned about using the cortisone ongoing, both because it is an immune suppressant, and basically further stimulates your body to produce the eczema response. Also, I didn't like DD getting it ongoing, even though I only used it once a day, before I went to work.
I used a homeopathic ointment instead called Unda 270, recommended by my ND. Whenever I got a split, I also used a homeopathic called graphites that helped to heal them up in about 3 days. I think the dosages was 30CH, about 3 pellets once a day til I noticed it healing up. The Unda wasn't quite as effective for the acute condition as the cortisone, but I felt it was a better option longterm.
Once I started taking acidophilus daily, it went away. There is definately a connection to diet and eczema. There was an article in Mothering on this about a year or two ago. I will see if I can dig up which issue it was in - I don't see the article online. Whether its yeast or eczema, the acidophilus would be helpful.
Most bfing resources seem to make a connection to eczema and introduction of solids. If its topical eczema, that might be the thing. Even if your baby is teething, the additional saliva perhaps is irritating to your skin? Some resources recommend having baby take a sip of H20 before latching on. I've had a history of on/off eczema all my life, and knew it wasn't topical. I tried to get DD to sip H20, but it didn't really work and was pretty impractical too.