I've had a similar concern for my daughter. Her hair goes down to her shoulder blades and is very dense. When I co-wash her hair I do so 2 inches away from her scalp. I use Dr. Bronner's diluted to wash her scalp, but not all over her hair, just the scalp. That seems to be working for her. Also, I use a travel size sprintz bottle with equal amounts of Tea Tree, Lavendar, and Peppermint essential oils (up to the 1/3 mark on the bottle, and fill the rest with aloe vera juice) and spray just the scalp to prevent itching and dandruff. I swear by this spray. I had a itchy scalp for months and noticed I was getting dandruff, it was unbearable. I'm surprised my scalp didn't bleed from all the scratching. I threw together this mix and the itching subsided immediately (not completely gone but better than it had been). After 15-20 minutes it was gone. So now I use it at least 2x/wk, more if I feel I need it.

Sorry for rambling but I hope this helps.
Natural since: 8/2011
Last BC: 1/20/2013
Curl Pattern: 4C
Porosity: High
Density: High
Texture: Fine
Hair Length: <TWA

"...For You formed my inward parts; You covered me in my mother's womb. I will praise You, for I AM FEARFULLY AND WONDERFULLY MADE; Marvelous are Your works, And that my soul knows very well..."