If you've ever suffered from an unbearably itchy scalp, you probably remember the experience well. Braid wearers are often afflicted with this problem. I've suffered from this myself when wearing braids in the past -- not fun. For me, there was an easy fix (take them out!), but the right solution greatly depends on what's causing the scalp itch in the first place.
This article on "why does my scalp itch?" may have the answer you need, whether you're wearing braids, cornrows, flat twists, a weave or not. Anyone with an irritating itch wants to get rid of it ASAP!