Pharmaceutical compositions for topical administration for the treatment of psoriasis are described, containing as active ingredient therapeutically effective quantities of 4,6-dimethyl-N-(3,4,5-trimethoxyphenyl)pyrimidin-2-amine (I) and 2,4-O-(2-furanylmethylene)-1,3,5,6-tetra-O-methyl-D-glucitol combined with suitable excipients and/or diluents.