Kim, I don't know if anybody has suggested this yet. There is a condition called "neurodermatitis". It comes on without warning and it's from stress, as the name implies. I was diagnosed with it after a very stressful situation at work a couple of years ago. My doctor knew about it because he had also been diagnosed with it. The only way to stop it is to:
1. Get rid of the stress asap.
2. Apply a prescription cream or an effective over the counter application.
3. Don't scratch it, no matter what you do.

The person that has it is in control of whether it stays or goes. If you continue to scratch it, it only continues and gets worse. You can wear gloves to bed if you need them to avoid scratching.

There's alot about it on the internet. I think you'll find that it might sound like exactly what you have. Good luck.