In the 2007 article, “A Practical guide to Scalp Disorders,” Ramon Grimalt, MD, of the University of Barcelona in Spain, reports that the high follicle density on the head combined with the high rate of sebum production makes the scalp a unique surface for infections and infestations that cause dandruff and flaking. Dandruff and seborrheic dermatitis affect about 50 percent of the world’s population; and although psoriasis only affects about two percent of people, 50 percent of cases occur on the scalp.
Zinc Pyrithione
Zinc pyrithione is an agent added to hair products for treatment of dandruff and flaking. It’s an antibacterial compound used to combat the fungus that can causes dandruff and seborrheic dermatitis, a condition linked to greasy scales on the head. In 2006, researchers at the University of Wales College of Medicine in Britain treated a group of 32 patients suffering from dandruff. In the study, half of each person’s head was treated with shampoo containing zinc pyrithione and the other half was shampooed with a placebo shampoo. The difference between the medically treated sides compared to the placebo side was statistically significant. There was a growing reduction of dandruff and flaking on the treated portions of scalp. Shampoos contain zinc pyrithione include Head & Shoulders and Equate Dandruff Shampoo.
Coal Tar Shampoo
Coal tar shampoo works by conditioning the scalp. Shampoos containing tar, like T/Gel shampoo by Neutrogena and Nova Pearls Medicated Coated Tar Shampoo, are used to treat seborrheic dermatitis and psoriasis by lengthening the life of skin cells, which minimizes flaking. Coal tar is also effective in treating inflammation and itching. The National Psoriasis Foundation reports that the higher the tar concentration, the more potent the product.
In 2001, the American Journal of Clinical Dermatology reported that shampoos containing tar solutions of up to 10 percent effectively treat scalp psoriasis. The paper found that tar’s most important feature is its ability to ease itching.
Salicylic Acid
Salicylic acid is an effective treatment for dandruff and flaking because of its ability to cause the outer layer of skin to peel and shed. It also helps soften skin affected by psoriasis and remove scales. In 2001, the International Journal of Cosmetic Science reported that in a double blind, randomized study, 19 subjects were treated with shampoo containing salicylic acid or zinc pyrithione. The patients shampooed twice a week for four weeks. Although both treatments were successful in treating dandruff, salicylic acid was slightly better at reducing the severity and scaling of their condition. Denorex is a shampoo that contains salicylic acid and conditioner.
