I've actually had a dry scalp, but when scratched no dandruff. I've also had dandruff, but not an itchy scalp. And, I've had a dry, itchy scalp with dandruff.

For me, if my scalp is itchy but no dandruff, then I need a tiny bit of oil massaged on my scalp. If I have dandruff, but no itchy scalp, then it's the product. If it's both, then I used too much product. At this point I usually dampen my hair, and rinse my scalp with water. The problem is gone.
Mod CG-Naturally Highly Porous and Dry
This list is not exhaustive...
Winter Regimen
Pre-poo: Hempseed oil
Cowash: HE The Sleeker The Butter, Trader Joe's Moisture Conditioner
Shampoo/Clarifier:various
PT:Not for a while...
DT:
Smooth Sexy Hair Sulfate-Free Smoothing Conditioner
LI/Detangler: It's a 10!, CURLS Cashmere Curls leave-in
Stylers: various
Sealers: Tamanu oil, The Body Shop Wild Argan Solid Oil

*experimenting and loving it!