I'll be simple. I'm a teen. Sometimes my head scalp gets really really really itchy and sometimes I just feel ( and sometimes do ) start scratching it like a friggin' monkey. BTW, I used to have dandruff problems a few years back, but i got a prescription, used the right shampoo and I'm done, I still use shampoo once/twice per week as recommended. I have noticed it gets really really itchy specially when I am outside. For exemple, everytime I walk to school in the morning, like 95% it'll be itchy on the way, dry or wet hair, then when I enter indoors it seems to go away slowly...

Anyone knows what's wrong? If you need some more questions answered just ask, thanks!