dry itchy scalp

Occasionally, on sides of my hair scalp, there are red spots and dry and flaky on some, also are itchy. Hardly any dry spots are  more than 5mm across, so we are talking a number of red/dry small spots rather than big area.
This happens only once awhile......and i don't know what is the reason!
I have been to my GP and told him about this, but he simply sent me to get some shampoo from the pharmacy for this problem, but it comes back again and again

I hope you can help me on this and advise me on what i can do.

My hair is fine and i would say that i have abit of greasy scalp.
I have to wash my hair daily from Mon- Fri ( as it would look lank) when i have to go to work. However, if i am not going out at the weekend, i will try not to wash my hair ( if i can)on either of this day or even both, so as to give the scalp a rest ! ( as i was told that it is not very good to wash your hair daily)
Hope this bit of info would help you?!

Thank You

Kind Regards,
Serene

[saz2008]

anyone got any ideas?