You are making me smile 🙂
Think of it like this, when you are young, the rate at which the body repairers dead cells and produces sebatum, the lubricant for the skin is quicker. But as we grow older this rate decreases. So it is possible that the skin underneath the grey hair is drier, coursing itchiness and flakes , or dandruffs. Of course there are also young people whose hair itches, because how oily our skins are is genetically determined.