I think a healthy scalp means your whole hair is healthy. A scalp can have many faults. Everything from being itchy, be coatet in dandruff and greasy to the more serious condition, psoriasis. I’ve had everything of the above. My psoriasis wasn’t that bad but never the less it bothered me. I’ve tried many dandruff schampoos but they never did what they should. More often than not they made my dandruff and itchy scalp get even more itchy and the dandruff didn’t go away.
During my psoriasis period I lost lots of hair because my scalp was covered in this layer of dead skin. It “suffocated” the roots of my hair and they fell out. The hair roots was covered in this nasty white psoriasis paste. Yuck.
I have used haircare that has worked but it has been hard to find. A while ago I found this. Vichy Micro Peel. It is a shampoo with peeling effect. You massage it in and it has to work for while. It smells good and removes dandruff. It makes my hair less greasy and you can feel the difference in your scalp after the first use. I don’t know how it works with psoriasis however I think it makes it better.