Dandruff is a harmless, chronic condition that occurs when the scalp becomes dry or greasy and produces white flakes of dead skin that appear in the hair or on the shoulders. People most often think of dandruff as anything that produces a flaky scalp.
Although it is harmless, dandruff can be embarrassing for those who have it. Dandruff usually starts between the ages of 10 and 20 and affects up to 40% of people over the age of 30.
Skin cells are formed continuously on the scalp, so the shedding of dead skin cells is a normal process. With dandruff, however, skin cells are shed at a faster rate than normal. Oil from the scalp causes the skin cells to clump together and appear as white flakes.
Dandruff can be caused by a number of things, including dry skin; sensitivity to hair products; and skin conditions such as psoriasis, seborrheic dermatitis, or eczema.
The overgrowth of yeast can also cause dandruff. This overgrowth can be caused by stress, hormones, too much oil on the scalp, or problems with the immune system.
Symptoms and Complications
The symptoms of dandruff include white flakes of dead skin in the hair and on the shoulders, as well as an itchy, red, or scaly scalp. Common dandruff flakes are usually scattered throughout the scalp.
If seborrheic dermatitis is the cause of dandruff, the symptoms usually appear gradually. The scalp becomes dry or greasy and feels itchy. As skin cells die, they turn to yellowish scales. A bad case of seborrheic dermatitis can also cause symptoms in other parts of the body. Yellowish or reddish scaling can appear on the hairline, in and around the ears, or on the nose and chest. Affected newborn babies may get a thick and crusty rash on the scalp, called cradle cap.
The flakes associated with psoriasis look like silver scales, which may also commonly be apparent on the ears, extremities, trunk, palms, and soles.
Making the Diagnosis
Dandruff is a condition that people can pretty much self-diagnose from the symptoms of an itchy, dry, and scaly scalp. Seborrheic dermatitis appears as reddish-looking skin with mild, greasy, yellow scales and plaques with indistinct margins. Psoriasis is often associated with silvery, scaly, well-defined plaques.
A doctor or dermatologist will usually make the diagnosis for seborrhea or psoriasis based on the appearance of the skin.
Treatment and Prevention
Dandruff can often be a chronic condition, but it can be controlled with the proper treatment. First, try shampooing with a non-medicated shampoo, massaging the scalp firmly, and then rinsing well. Frequent shampooing removes flakes, reduces oiliness, and prevents dead skin cell buildup. If this fails to help, special antidandruff shampoos are usually helpful. Instructions for use depend on the specific shampoo used. Some are used on a daily basis, while other are used only once or twice weekly.
When selecting an over-the-counter shampoo, look for antidandruff ingredients such as ketoconazole*, selenium sulfide, salicylic acid, sulfur, coal tar, or zinc pyrithione. You may need to try a few products before you find the one that works for you. Shampoos that contain ketoconazole appear to be more effective in the treatment of seborrheic dermatitis and dandruff when compared with other non-prescription medicated shampoos. Salicylic acid preparations are mostly used for dandruff caused by psoriasis, while sulfur and coal tar preparations are generally used for dandruff caused by seborrheic dermatitis.
If non-prescription preparations are not successful after 2 weeks, or if the condition worsens, you should consider seeing a doctor. A doctor may prescribe a corticosteroid lotion to be applied to the scalp. Never use corticosteroids for a long period of time without advice from a doctor. They can thin out the skin and cause other side effects.
For an infant with cradle cap, apply a small amount of mineral oil to the dry areas of the scalp to soften the scales and then shampoo it out. Then remove the scales by gentle brushing. You can then wash the infant’s hair with mild baby shampoo. If these measures do not help, try applying a small amount of warmed mineral oil at bedtime and then shampooing it out in the morning. If this isn’t effective, talk to your child’s doctor about next steps.
In general, corticosteroid shampoos and lotions are not used on infants, as infants absorb them much more easily through the skin than adults do. The good news is that cradle cap usually disappears eventually without any treatment within the first year of a baby’s life.
To help keep dandruff under control, shampoo frequently, reduce your stress levels, try reducing your use of hair products (e.g., gels and sprays), and eat a healthy diet.