The use of 0.25% zinc pyrithione spray does not enhance the efficacy of clobetasol propionate 0.05% foam in the treatment of psoriasis.

Background: It was discovered that Skin Cap (Cheminova Internacional S.A., Madrid, Spain), an over-the-counter psoriasis therapy with zinc pyrithione, contained clobetasol propionate and it was withdrawn from the market by the US Food and Drug Administration review.