Dry scalp is most common during the winter because the air is cold, which chaps the skin. Heating systems pump out hot, dry air to further dry out the scalp. Another common cause of dandruff is infrequent shampooing or hair washing. 

If the hair is not cleaned at least twice a week, then skin cells and oil can accumulate on the scalp. The oil accumulation can cause the skin to dry out and flake. There are other skin conditions that lead to dryness such as fungus, psoriasis, dandruff and eczema.

We have a dry scalp treatment and a Scalp Anti-Bacterial Formula / Scalp Fungus Treatment that may help.

Please look at the Scalp Anti-Bacterial Formula / Scalp Fungal Treatment and possibly the vinegar rinse to help stop the itching.

Here are links to them-