I've suffered from your issue also!
here's what I use. i use Arbonne Tea Tree Oil Shampoo ($25) and Scalpicin from (Rite Aid, etc.)
I lather the Shampoo up real good and let it sit on my scalp for 5 minutes. then i rinse and condition.
When i get out of the shower, I towel dry my hair and then apply the Scalpicin to my scalp in the itchy areas. Really stops the itching while the Arbonne shampoo heals the scalp.
You can find the Scalpicin at any drug store. The Arbonne tea tree oil shampoo you can find on a ton of websites. here's the one I use LKEssentials.myarbonne.com