Kevscar
I can understand your reluctance to have to deal with yet another specialist who is unlikely to know about CRPS. I've had a great deal of personal experience of the frustration and risks of dealing with people who have never heard of the condition or, worse still, try to pretend they know about it but patently don't.

That said, there is very little about dermatology that is invasive so the risks for you in just going to see someone for an opinion are minimal. If your GP refers you properly, he or she will make the consultant aware in the referral letter that you have the condition so that they are forewarned that there is a complexity that they must be aware of.

There isn't a single CRPS rash - the condition can cause all sorts of different skin problems, rashes and lesions which is why it's really important to get yours checked out in case its actually something unreleated. Even if it is related, the dermatologist may have more ideas about topical treatments that could make your life and your skin much better. Once skin breaks down it can cause critical problems that are very hard to treat.

You can always say no if you aren't happy with any tests or treatments that are suggested but wouldn't it be better to at least have the referral and get an opinion?