Winter heaters and fireplaces dry out our skin, short of any other symptoms your scalp is probably dry. It could help a little if you didn't have to wash your hair everyday, which contributes to dry, itchy scalps.
Probably dandruff like me mine gets itchy too :c. Try using a home made remidee i found online. You'll need 1 teaspoon of brown sugar 1/2 teaspoon of honey 1 teaspoon of apple coder vinegar Mix them all together in a little container until you get a thick paste. Take a shower and after shampooing once rinse it out and apply the remedee to your scalp.massage it and make sure its all on their. Leave it on your scalp for about 5 minutes after that rinse it out and shampoo your hair again. Do this once a week and youll be fine. c: hope i helped.
It could be dry skin like stated above, or you could be taking showers that are too hot. I know some people are sensitive to hot water, and get rashes on their body if the water is too hot. I'm not sure if you can get it on your scalp, but try taking cooler showers.
Your face and skull must be oily, work place may be having dirt, or polluted with smoke or something like that. May be you have to travel too much, or working in a humid atmosphere. You may not be using soft water(sweet) for bath. Must use shampoo at least to save yourself from this problem.