External cortisone in various different bases, can help Psoriasis, but this help usually lasts only for 1-2 days at the most. There are certain areas such as the ears and the backs of the hands where tar treatments are not very helpful, and in these areas cortisone applications are usually best.

However, in general, it can be said that the tar applications are the treatment, and cortisone applications provide some help.

Internal cortisone tablets are best avoided in Psoriasis unless every other treatment has not helped. The main problem with these tablets is that they may help, but when they are stopped, the Psoriasis can suddenly flare up and become worse than it was originally.