Low-dose corticosteroid creams, lotions, oils, sprays, foams, gels, and ointments are called topical medicines. They target the inflammation related to psoriasis, and work very well for many people. Be careful not to use too much of them, especially stronger ones. That can lead to stretch marks or make the thin skin in these areas even thinner. It’s also not a good idea to cover these areas with plastic bandages, since they trap moisture.