Hello and welcome to healthcaremagic
Psoriasis can affect the scalp as well defined plaques with adherent, thick scaling. Unfortunately the disease can relapse after seemingly complete cure. The course of psoriasis is indeed marked by remissions and relapses and available treatment options can only induce the disease into remission, rather than permanently cure it.
For
scalp psoriasis, I prefer to start my patients on a coal tar+
salicylic acid based shampoo. Along with that I also ask my patients to apply a potent
topical steroid lotion with or without salicylic acid, twice daily.
Since psoriasis is a steroid responsive dermatosis, it responds very well to topical steroids, which must be gradually tapered to prevent a rebound flare.
Alternative to topical steroids are topical Vitamin D analogues like
calcipotriol lotion, which are steroids sparing agents and are thus devoid of the side effects commonly encountered with long term steroids use.
These are prescription medications, I would suggest that you consult your
dermatologist before trying these out.
Regards