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 SPRING REGIMEN-This list is not exhaustive...
Pre-treat: coconut oil
Clarifier:hiatus for now
Cowash: HE The Sleeker The Butter, HE NOYF w/Mandarin
PT: hiatus for now/DT:Redken Diamond Oil Deep Facets, Living Proof PHD
LI/Detangler: CK Satin Roots, Nu-Gro Leave-in
Oils: tamanu/Moisturizers: various
Stylers: CK Curl Factor, AH Cupuacu & Burdock Sweet Hair Pudding
*experimenting and loving it!