Your dermatologist is correct, psoriasis has no cure at this stage, however that doesn't mean you can't successfully manage it so that you reduce the frequency and intensity of flare ups in your skin.
You can clear your skin by focusing on reducing inflammation in your body instead of focusing on the suppression of your immune system. This is achieved by changing the way you eat and live so that your body is healthy and there is no inflammation.
Just because there is no cure, it doesn't mean we need to remain sick.
To simply say there is no cure and you must stay on immune-suppressant medications does nothing to deal with the disease but simply takes you awareness away for a short period of time.
Psoriasis is linked to a number of different illnesses. By living your life the anti-inflammatory way, means you will be preventing the possibility of such diseases from developing. Although there is the genetic factor in play, what we do and how we live is just as important if not more important.