Sorry about this problem Deb.
I have it on my hands and feet. Sometimes it gets worse, sometimes better. Done all the topical and oral steroids in the world and still is here. Have they tried some of the new "light box" treatments. I have not done those.
Watch out for ingrown toenails. It attacked my feet terribly about 6 years ago and took forever to get my toenails semi-normal again. I went to a podiatrist to have the nails cut correctly to ease the pain and make suggestions.
It is now on the arches of my feet only and hasn't attacked my toes recently. My hands are a mess though.
Good luck with your dermatologist. They tell me it is stress related -- can't do much about that!