Gosh I've read that exposure to the sun can help eczema but I'm not so sure I would want to do the tan bed thing due to the cancer risks. I would talk to your dermatologist and see what they say. I would be very interested to hear their position.
I read on this board that someone had used it for seborric dermatitis and it had cleared it up, I don't normally use tanning salons but I figure for 5 minutes once a week as I only have it on my face it might help
Some years ago I managed a tanning salon. We had a few people with eczema and psoriasis that used the tanning beds upon recommendation from their doctors. (Tanning salons will not and cannot make the claim that tanning will help with these conditions.) Many found great relief. They really thought a little light helped their skin. You just want to make sure you don't over do it and you should check with your doctor. And yes a tanning bed can be just as damaging as real sunlight.