Try buying roobious tea from any supermarket and rubbing the tea bags on your effected skin, and bathing in a bath with some tea in it.
This has worked for several people I know with substantial, life long psoriorsis including myself.
Its not a cure but it is a very effective treatment, it works aswell or better than steroid creams in my experience and from close friends experiences too. It vastly improves the appearance.
There is no special brand or formula or routine, I don't know of any side effects but obviously this is just a tip from my experience after suffering my entire life and this been the best advice I can offer!
I am not usually a herbal or alternative fan, but I was desperate to try anything and extremely glad I did! Its cheap to try and to my knowledge there's no side effect. I suffer uti infections from using soap in the bath and bathing in the tea doesnt even trigger that.
Also my gp advised I use a cream called aveeno on my eyes as they get very dry skin that then cracks n swells on the lids,more eczema like than popsoriorsis and its changed my life. I only started suffering after developing an allergy to I think but I'm not 100% ibuprofen and my eyes puffed up and were swollen shut, about 18 months ago. Also hydrocortisone 1% cream occasionally on my eyes also works a treat. This also works if people have seasonal allergies, I've suggested this to a few friends with watery sore dry eyes suffering allergies and they have all been extremely grateful to the point it changed their lives. They can now wear make up again! It can be bought over the counter. I was told once by a nurse it would thin my skin and was highly dangerous and didn't use it and suffered for a few months until I saw a dermatologist who was furious I was told that! Its safe, they regularly use it on eyes, babies, genitals (its in thrush cream if you look). Thankfully pharmacists seemed more informed when friends have bought it over the counter, they have been supported by the pharmacist. Its much cheaper over the counter say £3 than the £7 odd prescription from a gp.
Fake tear eye drops have also been a god send. Avoid the whitening ones as they can have a drying effect even though they help with the redness. These eye drops are on supermarket isles, drug stores, chemists. No brand preference. Fab for irritated eyes.
Hope I can help just 1 person, I know my life was miserable at times without others advising me.