How to Treat a Dry Itchy Scalp

You can try tea tree oil.

try 'tea tree oil' shampoo. I found some in the 'natural' section of my grocery store. Cheapest one was $6, but it's a nice size bottle. Bought it for my son who had some flakes. Worked well. Flakes are gone. Smells good - kind of minty.

I put straight olive oil on my hair. It worked for the Egyptians! A couple times a year I heat cheap olive oil in the microwave and massage it into my scalp, then work it onto my dry hair. Cover with a plastic shower cap and heat with a blow dryer. I rub whatever oil might be left onto elbows, knees, and feet. I let it set 20 minutes then take a long hot soapy shower to wash it out.

I've switched to an all natural shampoo and that has worked for me.

try tea tree products they have store brand too,my husband has this also he can only use the tar based shampoos and conditioners they seem to help him a lot

Have you tried the clinical strength Head & Shoulders? It has a different treatment ingredient than the regular ones, and it works really well. It is ph balanced so even if you don't have dandruff, it treats your scalp kindly and can help with itchiness.
Good luck!