Hi there, I have primary sjogrens and have a dry itchy scalp too, I use a tar based solution just from the chemist and it eases the itching a bit but not completely, my biggest advice is dont wash youre hair too often, as that just brings out the oils more, and also even though its really hard, try not to itch it!!! as that makes it miles worse, mines worse right at the front in the middle, and if i itch it its very visable to see, so ive just tried not to for a week and its got better, the tar based shampoo stings on the areas i had itched as the skin had broken, but overall it seems much better. Hope this helps in some way and it eases up for you.
Ihave sjogrens and psorisis and find fish oil tablets control dry scalp and other areas of dryness. I ran out of them the other week and within 4 or 5 days my scalp was so dry and itchy it was driving me nuts, so for me they really work well.
i shave my head bald and use a topical steroid. if i let my hair grow a bit it starts bothering me again. it also hides the fact that i have lost more than half my hair, giggle.