The solution I have found for this problem (and for the problem of having to go out when my hair is filthy) is to make my own dry shampoo.
The commercial ones all have stuff I won't use, so after experimenting a while
arrowroot powder alone does the trick!
You can buy a big bag of
Bobs Red Mill brand for about $4 and it will last you for years. You can add essential oil, or cinnamon or what have you, but in the end
I just like the arrowroot powder alone.
I bought a makeup
powder brush, and I just dab the brush in my jar of arrowroot, (tapping off the extra,),and dab it on my scalp by making
parts every inch or so.
You *can* do too much, so less is more. After you've applied it to your satisfaction, you can brush, comb, or finger it through.
This really helps the itchy/painful scalp thing! It also makes you presentable if your hair is seriously greasy and you have to meet and greet.
I use this trick all the time, and am so very glad for it, because washing hair is just not gonna happen on the regular over here.
Sometimes it actually makes my hair nicer than when it is clean!