Suggest Treatment For Psoriasis That Aggravates In Winter Season

I am a 51 years old woman suffering from Psoriasis since last 3/4 years. Doctor prescribes me 1) Acitratin 25 2) Rolsical Oint 3) Deflorate oint. Earlier they worked but in this winter they are not responding. My problem aggravates during winter anr dry seasons.