Methods, compositions and kits for treating psoriasis and other autoimmune diseases in human or animal subjects. The disclosed methods generally comprise administering to the subject a therapeutically effective amount of a naturally occurring or synthetic agent comprising estriol or another estrane, estrogen or estrogen receptor-effective composition. The disclosed compositions and kits generally comprise topical preparations and/or combination preparations wherein 2 or more agents are combined for either simultaneous administration or administration at different times and by the same or different route(s) of administration.