A red, itchy, scaly scalp is likely more than just dandruff. It could be seborrheic dermatitis, a long-term inflammatory skin condition. The infantile form of seborrheic dermatitis, known as cradle cap, typically clears up within the first year of life. The adult form, however, usually persists and requires treatment to keep the condition under control. Adult seborrheic dermatitis (ASD) appears to be caused by an inflammatory response to a type of yeast commonly found on the scalp and skin. In addition to the scalp, ASD often affects the eyebrows, eyelids, ears, nasal folds and chin. Treatment of scalp ASD typically includes use of one or more types of medicated shampoo. Other topical medications might also be recommended for stubborn o severe flareups.
Scalp ASD is characterized by greasy, scaly, itchy patches of accumulated skin cells. The entire scalp can be involved in severe cases. Keratinolytic shampoos loosen the scales so that they can be washed from the scalp and hair more easily. The active ingredient in keratinolytic shampoos is usually salicylic acid, with or without sulfur. Over-the-counter salicylic acid shampoos (T/Sal, Keralyt) typically contain 2 to 5 percent salicylic acid. Some keratinolytic shampoos contain a combination of salicylic acid and sulfur (Sebex). The sulfur also acts to loosen scalp scales and might reduce the levels of yeast on the scalp.
Coal Tar and Zinc Shampoos
With seborrheic dermatitis, the normal rate of skin cell proliferation is increased and there is buildup of dead cells at the skin surface. This abnormality is called hyperkeratinization. Coal tar and zinc shampoos can be helpful for scalp ASD at least in part due to normalizing this process. Over-the-counter coal tar shampoos (T/Gel, DHS Tar Shampoo, Denorex) contain 0.5 to 1.8 percent coal tar. Zinc shampoos (Head and Shoulders, Selsun Blue) are commonly marketed as antidandruff shampoos, and typically contain about 1 percent zinc pyrithione.
Several species of a type of yeast called Malassezia are believed to contribute to the development and persistence of seborrheic dermatitis. Therefore, antifungal shampoos are commonly recommended to treat ASD, and have been shown to alleviate symptoms. Over-the-counter brands of antifungal shampoos (Nizoral A-D) typically contain 1 percent ketoconazole, a substance that limits the growth of fungus. Prescription antifungal shampoos contain 2 percent ketoconazole (Nizoral) or 1 percent ciclopirox (Loprox).
Combination Products and Other Topical Treatments
Reading the label is important when looking for an over-the-counter shampoo to treat scalp ASD. There are many products available and they often contain a combination of ingredients to target different aspects of the problem. Additionally, kits are available without a prescription that contain several different shampoos (Denorex Kit) to be used in rotation. For people with severe scalp ASD, a prescription steroid shampoo (Clobex) might be recommended for short-term use. Creams and leave-in products that contain one or more of the same active ingredients as the shampoos may also be recommended.
Next Steps and Precautions
Many people with scalp ASD are hesitant to mention it to their doctor due to embarrassment. But it's important to enlist your doctor's help if you have this problem. Scalp ASD typically doesn't go away on its own and recurs even after periods of apparent improvement. Additionally, there are other skin disorders with similar symptoms. Visiting your doctor will enable you to receive an accurate diagnosis and appropriate treatment.
Initial treatment for scalp ASD typically includes daily treatment with medicated shampoo, with or without leave-in medicines. Various medicated shampoos have different drawbacks and potential side effects, such as hair discoloration, skin irritation or an allergic reaction, which your doctor will explain. After your symptoms improve, a maintenance program with weekly treatment using medicated shampoo is often needed to keep the condition at bay. It's particularly important to seek help if your scalp ASD also involves areas of your face or neck, as different medicines are needed to treat these areas.
Reviewed and revised by: Tina M. St. John, M.D.
- American Family Physician: Diagnosis and Treatment of Seborrheic Dermatitis
- Journal of Clinical and Aesthetic Dermatology: Adult Seborrheic Dermatitis: A Status Report on Practical Topical Management
- Evidence-Based Dermatology, 2nd Edition; Hywel Williams, et al.
- Pharmacy and Therapeutics: Seborrheic Dermatitis