There is a variety of shampoo options available for treatment of psoriasis and it is up to you to find which products work best for you.
I settled on two types. One is a tar shampoo and the other is a salicylic acid shampoo. I find it best to alternate between the two for best results, using one the one day and the other the next day.
Years ago I was having a haircut and my hairdresser told me that I should rinse my hair more thoroughly because she could smell the chemicals on my hair and she thought that was bad. A few months later we had a Psoriasis Association public meeting and the speaker was a leading Cape Town dermatologist. I asked her how thoroughly the shampoo should be rinsed out and she said that it is more beneficial to rinse very briefly than to rinse thoroughly. She said that keeping some of the chemicals on the scalp makes it work better.
There are a few other points that I have learned over the years to help keep the psoriasis on my scalp under control. So, here are points in no particular order of importance.
1) Medicated shampoos need to be on the scalp for awhile to work, so it helps to wet the hair and rub in the shampoo a few minutes before getting into the shower. Maybe lather up, then brush your teeth, shave etc before entering the shower.
2) The shampoo is needed on your scalp rather than in your hair. No problem if your hair is short but if it is very long then you can lose a lot of beneficial shampoo in your hair. Concentrate on massaging the shampoo into your scalp with your finger tips.
3) Don't overdo the rinse. A quick rinse with warm water is all that it needs. Don't make the water too hot, excessive heat will aggravate your psoriasis and also remove more of the chemicals than warm water.
4) Salt water helps my skin. If I have been in the ocean then I don't rinse with fresh water when I leave the beach but rather allow the salt water to air-dry. I don't wash my hair the next day but leave the salt on my scalp for another 24 hours.
5) It helps for the sun to get to my scalp, so I seldom wear any sort of headgear unless I will be in strong sunlight for many hours. I want the sun to penetrate through my hair. I keep a cap handy to wear if I feel that my scalp has had enough sun.
6) Being somewhat of a skinflint, I don't like to have my hair cut too often. When I have it cut, it is with a razor and #4 or #5 attachment. That is short, so it lets the sun through. When it grows to about 50mm (2") I have it cut back again.
Using these methods, my scalp is generally pretty good. It is still worthwhile to wear mostly light coloured clothing to be sure that there are no flakes of skin showing on my shoulders. Black is out, charcoal is OK, grey is good and white is great.