I feel your pain - I have it all over too, especially on my face and scalp. If you're not already avoiding sulfates, do. That's helped me as much as anything.
You might try adding a few drops of pure tea tree oil to your shampoo or co-washing conditioner when you wash your hair. If co-washing, I'd try putting some of the oil in the conditioner and massaging it into the most affected areas of your scalp (on dry hair) 15-20 minutes before you actually wash it, giving the tea tree oil more time to do its thing.
Or (don't think I do both) you can dissolve some plain, cheap aspirins in your regular shampoo so that you're getting some salicylic acid without harsh medicated shampoo.
Again, scrub the scalp well, be it with your finger tips or with a shampoo brush.
An apple cider vinegar rinse once a week can help the itch because it stabilizes the pH level - but no more often or it can be drying. One to two tbsp. vinegar to 1-2 c. water after you wash your hair. I pour mine on before my conditioner, and it doesn't leave any lingering smell at all.
I nearly always use about a half dollar's worth of either plain FOTE AVG or Aubrey Organics Moisture Maniac (aloe is its main ingredient, too) on my hair first thing out of the shower, and I also massage it into my scalp, which seems to sooth it some and add some light, non-greasy moisture. I used to swear by the AVG, but now more often than not, I use the AOMM - it has some other ingredients that also seem to agree with my scalp and hair. If I use leave-in, I add a little after
Glycerin's not bad for your scalp, but it can be drying for your hair in winter when the dewpoint and humidity are low because it's a humectant and can draw moisture out of your hair when there's none in the atmosphere.
In my case, I find that I usually start getting itchy (and then can get broken, crusty,weepy places, too) after a few days. I have the best results when I either lo-poo or co-wash every 2-3 days, but I often stretch it longer than I should - and pay for it!
Use heat on your scalp as little as you can - I know, that's hard in cold weather, but keep it as low as you can.
Haven't needed to do it in a while, but I used to have some luck applying either Vitamin E gel or oil to my itchiest, scaliest areas in my hairline before bedtime. I usually had to wash the next morning after this, though.
Both my hair and scalp enjoy this:
Even though their products are targeted at African American hair, many other finer, looser-curled curlies love many of them, too. This one is my favorite of all their stuff I've tried - I try to use it once a week, massaging it into my scalp and hair and leaving it on for about an hour, usually with a little heat for about 10 minutes of that time.
Hope you find something
here that helps!