don't shower too much
soaps should be avoided.
Regular sea water baths and application of sea water externally over the affected parts once a day are beneficial. epsom salt is really good for psoriasis.
finally after suffering more than 40 yrs from psoriasis,I found peppermint pure organic oil very helpful after shampoo I add few drops to about 4c off water,and rinse my scalp with it, and leave it don't rinse again.