This time of year we see many patients with concerns over a stubborn dry scalp. Winter can defiantly increase dandruff for those already prone and cause dandruff (or simpler, dry scalp) for those with typically normal scalps. Other triggers such as lack of nutrition, chronic diseases and stress can also increase or cause dandruff.
 A technical dry scalp is caused by soaps or detergents or dry weather. A dry scalp can be relieved much as you would relive dry skin- conditioners, oil treatments, and so forth. Most tend to blame dryness for their flaky itchy scalp, but on the contrary, the symptoms can also be those of seborrhea, which is caused by an overgrowth of yeast that feed on sebum (scalp oils). This causes actual dandruff which is characterized by more yellowish flakes, that are larger and harder to remove than dry scalp flakes. 
Psoriasis and Eczema also occur on the scalp, so be sure to see a dermatologist if your scalp becomes scabby, severely itchy or irritated or your conditions continue to worsen with over the counter treatments.
If you are suffering from dandruff try these over the counter products recommended by our friend in Dermatology, Dr Jessica Wu, of Hollywood, CA.

If your hair is oily and needs to be deep-cleaned, try Head & Shoulders Citrus Breeze, which has grapefruit oil and green tea extract to leave your hair smelling fresh.
For dandruff and damaged hair, try Head & Shoulders Damage Rescue, which contains vitamin E and dimethicone to coat and strengthen weak, brittle strands.
If itching is driving you crazy, try Head & Shoulders Itchy Scalp Care, which contains eucalyptus to cool and soothe an itchy scalp. (Be careful when rinsing; this can sting if it gets in your eyes.)
If your dandruff is especially stubborn, try Head & Shoulders Clinical Strength, which contains 1 percent selenium sulfide to fight yeast and seborrhea.
Men should try Head & Shoulders Men, which comes in several versions, including Active Sport, with 1 percent zinc, and Hair Endurance (to restore volume to thinning hair).
Marguerite Germain