To keep psoriasis
under remission, you may try these
1) scalp- use a tar based shampoo. Also apply a steroid salicylic acid
lotion daily over scalp lesions
2) elbow and knee- use mild soap to bathe( dove, venusia, cetaphil
etc). Moisturise skin by applying cotaryl or moisturex cream. Apply a steroid salicylic acid based ointment over the lesions.
It is always better to use prescription drugs under a dermatologist's follow up, so kindly consult a dermatologist
Hope that answers your query. Take care.