Daughters head started itching several weeks ago, now mine is. We have used head & shoulders and also T-gel (coal tar) by Neutrogena.
Tried to figure out what is causing it. Have not changed products but started using an Ionic Pro air cleaner. Wondering if it is drying the air out to much for us??
Have you checked for lice? My sister got it from trying on a hat at a store and had it for like 2 months before she knew it. Otherwise see if it is your water. If we are low on salt in the water softener I get a really itchy scalp.