tea tree oil

First off are you sure it is psoriasis? Sometimes the flora of the scalp gets out of balance, either from shampoo or other chemicals ie dyes applied to the head. In either case applying a treatment of yogurt onto the scalp can be really nourishing. Just rub the yogurt into the scalp and put a tow on the head. Then let it sit there for 30-60 minutes, the rinse. I would also rub live oil into the scalp. I would not use essential oils as they can be dyring and can also mess of the flora. I often use lavender or calendula infused in olive oil (the whole fresh plant), on my scalp. Chickweed is specifically recomended for helping psoriases and again an infused oil of the plant or an infusion or tea used as a hair rinse.
Hope that is helpful.
Blessings
Linda

The things that helped end my psoriasis outbreaks were learning how to remove the stress triggers in my life as well as letting sunlight go on my scalp as best as I could... Havent had any outbreaks in years. :)

I know someone's who's psoriasis cleared up 90% after they quit cigarettes.

Also I have heard of some success with taking herbal supplements to help cleanse the liver and kidneys, in order to reduce or clear up the symptoms of psoriasis.