A dry, flaky and itchy scalp can be caused by a few different conditions. Dandruff, the most common condition with these symptoms, occurs when the renewal of skin cells on the scalp is accelerated and more apparent. Seborrheic dermatitis, a form of dandruff, can make hair look greasy and flaky. Scalp psoriasis is very similar to seborrheic dermatitis, but produces larger flakes, and can affect other parts of the body.
Zinc Pyrithione
According to the Mayo Clinic, shampoo containing zinc pyrithione has antibacterial and antifungal agents that can reduce dandruff-producing fungus of the hair and skin. Zinc pyrithion can also be used to treat seborrheic dermatitis and psoriasis. Head & Shoulders contains zinc pyrithione.
Ketoconazole Shampoo
The University Medical Center Sart Tilman in Belgium studied a group of patients with dandruff and seborrheic dermatitis. Subjects treated with ketoconazole, a broad-spectrum anti-fungal, had a 70 percent improvement in their dandruff. Their relapse rate was significantly reduced as well.
Very few side effects were recorded. One shampoo containing this ingredient includes Regenepure DR Scalp Treatment.
Salicylic Acid
For stubborn dandruff, salicylic acid, sold as a foam or shampoo, works by increasing skin hydration. Omni Medical Search reports that salicylic acid "loosens the dead skin cells so that they can removed or washed out more easily." Neutrogena T-Gel Shampoo contains 3 percent salicylic acid.
Selenium Sulfide
Selenium sulfide has been used since at least the 1960s for treating dandruff and seborrheic dermatitis. Prescription and over-the-counter shampoos containing selenium sulfide, such as Selsun Blue Medicated Treatment, work by slowing skin cells from drying.
Although a proven treatment for these conditions, research from Queen's University in Ontario, Canada, found that it is not tolerated as well as other scalp medications.
