There are a few OTC topical medications which may help psoriasis. Many of these are coal tar derivatives, which have a distinctive odor. Coal tar products can increase the sensitivity of the skin to sunlight and cause a sunburn in those unaware of this. On the other hand, coal tar medication applied carefully directly to psoriasis plaques an hour or so before natural sun exposure is also a potent treatment in and of itself.
Topical corticosteroids in OTC creams are limited to hydrocortisone 1%. Although somewhat weak, this strength of hydrocortisone can sometimes be quite effective for psoriasis of the face, armpits or groin. It's just too weak to treat thicker plaques on the elbows, knees, hands and feet however.
Finally, good 'ol petroleum jelly has been shown to be somewhat helpful in treating psoriasis -- just be prepared for a little bit of a mess.
