
Skin diseases such as psoriasis, namely: psoriasis punctata, herpes simplex and mycosis fungoides are treated by administering (either topically or orally) to an afflicted subject an effective amount of monofunctional derivative of the formula ##STR1## wherein R.sub.1 is --COOR.sub.3 or --CN; R.sub.2 is --H or --CH.sub.3 ; and R.sub.3 is --H, --CH.sub.3 or --CH.sub.2 CH.sub.3.











