Hey deepu125, I have always had scalp psoriasis that changes in severity in accordance to weather, stress etc. I have tried a few things from my doctor, I found coal tar shampoos particularly useless and dovonex didn't do much either. He recently prescribed me Xamiol, which is a calcipotriol/betamethasone gel which you use overnight and wash off and it's so so useful as it helps the flakes come loose, which can be messy but has a lasting effect. As far as preventing flare-ups, well..I don't think you can with psoriasis, you can just do what you can to help delay them such as look after yourself, drink water, don't get stressed etc.
Hope I helped
