About dandruff. Dandruff — excessive scaling of the scalp — affects more than 50 percent of the population. It may be due to stress or a chronic or recurrent skin disorder, such as seborrheic dermatitis, but the most likely cause is infection by Pytyrosporum ovale fungus. This fungus is found naturally on the scalp but some people are more affected by it than others. It feeds on the skin’s natural oils and causes irritation and shedding of dead skin. Many people shed flakes of dandruff, especially in winter, when the scalp may be dry. But some people have a hereditary tendency to develop skin problems that are triggered by a sensitivity to specific foods. Because the offending food varies from one person to the next, the only reasonable advice is to avoid foods that seem to make dandruff worse.
Treatments. Some cases of dandruff may respond to flaxseed oil, which seems to help itchy skin conditions such as psoriasis and eczema. Take 1 to 2 teaspoons a day. You’ll need to wait several weeks or months to see an effect.
To control mild dandruff, doctors usually recommend shampooing daily until the dandruff is under control, followed by twice weekly for maintenance. Dandruff shampoos contain zinc pyrithione, tar, or selenium sulfide, all of which work as exfoliants to hasten the shedding of the dead cell layer from the scalp. If these do not work well, shampoos that contain the antifungal medication ketoconazole can be tried.