Calcipotriene
"I have been using this for a scalp condition called  Lichen planopilaris  somewhat related to psoriasis, however it affects the hair follicles on the scalp. After a week of use I noticed significant improvement in itching and scaling. It is going on 6 weeks now, and I continue to see slow but steady progress. What I really want to emphasize here is that I found out the hard way that this product is extremely toxic to cats. Even a small amount can be deadly. My cat drinks in the shower bottom after I shower this off each morning, and he became very ill. After costly vet bills, we were able to save him. Please be very careful with this around your pets."