Scales on the scalp may be caused by several different conditions, including psoriasis, seborrheic dermatitis and ringworm. According to MayoClinic.com, psoriasis typically causes thicker scales that look drier compared to seborreheic dermatitis. Ringworm produces painful, scaly patches that also cause hair to break off. Medicated shampoos can help you control these conditions and get rid of scales and flakes.
Selenium Sulfide
Shampoos containing selenium sulfide can help to kill ringworm spores and to control seborrheic dermatitis, according to MayoClinic.com. These are available over-the-counter and come in different concentrations -- between 1 and 2.5 percent. Wash your hair with the shampoo once or twice a week for a month, and leave it on for about 5 minutes during each wash, advises MayoClinic.com.
Ketoconazole
The shampoo sold under the brand name Nizoral contains an ingredient called ketoconazole, which can also control psoriasis and seborrheic dermatitis. Ketoconazole has antifungal properties and binds to the natural protein in hair to remain effective between shampoos, according to the manufacturer, who recommends using it twice a week and points out that it is gentle enough for African-Americans -- who have more fragile hair that breaks easily -- to use to tackle scaly scalps.
Coal Tar
This ingredient found in medicated shampoos is among the oldest and most widely used treatments for conditions such as psoriasis and seborrheic dermatitis, according to the American Osteopathic College of Dermatology. In shampoos, it's available in concentrations up to 2.5 percent. However, coal tar increases your sensitivity to ultraviolet light. Wear a hat or cover your head with a scarf if you plan to be outdoors for any length of time. It can also stain your clothes or bed linens, so use an old towel after shampooing with it, and protect your pillowcases.
Salicylic Acid
Better known as aspirin, salicylic acid can also be found in nonprescription medicated shampoos for seborrheic dermatitis and psoriasis. Salicylic acid is a peeling agent, or keratolytic, and promotes shedding of the outer layer of skin, accoding to the National Psoriasis Foundation. It's effective at softening and lifting scales. However, do not use it excessively or leave it on for too long, as it can also irritate skin and cause temporary hair loss.
