What Is Dandruff?

Dandruff is a very common skin condition, involving skin flakes, itching, and mild redness of the scalp. It is estimated that dandruff—along with a more severe skin condition called seborrheic dermatitis (SD)—affects 50% of the adult population in the United States.

Learn more about the types, symptoms, causes, and treatment of dandruff.

Types of Dandruff

There are several types of dandruff, including:

• Dry skin–related dandruff: This is the most common type of dandruff, which usually occurs during the winter months (from cold, dry weather) and is linked with using hot water to shampoo the hair (which dries out the scalp). 
• Oil-related dandruff: This occurs from a buildup of sebum (oil) on the scalp. The oil can clump the dead skin cells on the scalp together with oil, forming itchy flakes.
• Yeast-related dandruff: This is caused by Malassezia yeast, which is a type of fungus that lives on excess oil. It produces a byproduct that causes the skin cells to clump together, which is the cause of the white flakes seen in dandruff.

Dandruff Symptoms

Often the first sign that a person has dandruff is the appearance of white flakes of dead skin on the hair or shoulders, as well as an itchy scalp. Other symptoms of dandruff can vary, depending on the type of dandruff.

Symptoms of dandruff may include:

• Dry, flaky skin that worsens when the weather gets cold
• An itchy scalp
• Whitish-yellow skin flakes on the scalp, hair, eyebrows, beard, or mustache
• Flare-ups that occur in cold, dry seasons and during periods of stress
• Mild redness in the affected area
• Oily skin on the scalp

Causes

Although the exact cause of dandruff is not well understood, some experts surmise that it is the result of too much oil (sebum) from the oil glands (sebaceous glands). Sebaceous glands are located in the hair follicles, and they produce the oily, waxy substance that lubricates the skin and hair, called sebum. 

A type of fungus called Malassezia yeast may also be instrumental in the development of dandruff because this yeast grows in the sebum.

Risks

Factors that increase the risk of getting dandruff include:

• Having excessively oily hair and skin on the scalp
• Being a certain age (people from young adulthood to middle age have a higher risk of getting dandruff than do older people)
• Having a health condition that causes a compromised immune system, such as cancer, an organ transplant, or HIV/AIDS
• Having a neurological disease (such as Parkinson's disease)
• Being a male (some studies show that the prevalence of dandruff is higher in males than in females)
• Stress
• Lack of sleep

Diagnosis

Dandruff is normally diagnosed by a history and physical examination. There are usually no lab tests needed for diagnosis, but a skin biopsy may be performed to rule out other conditions.  

Treatment

Dandruff in adolescence and adults cannot be cured. Dandruff treatment is aimed at alleviating symptoms and minimizing visible signs of the disorder (such as redness and itchiness) and preventing flare-ups. Treatment depends on the type of dandruff and how severe the dandruff is.

Mild dandruff can usually be treated with a gentle shampoo. Shampooing daily can reduce the oil on the scalp and prevent the buildup of dead skin cells.

Moderate dandruff can usually be treated with an over-the-counter (OTC) dandruff shampoo.

Types of OTC medicated dandruff shampoos include:

• Selenium sulfide shampoos: These help to slow down the rate of skin cell death (lowering the accumulation of dead cells). They may also help reduce the fungus that can contribute to dandruff.
• Zinc pyrithione shampoos: These work on reducing the fungus that can contribute to dandruff.
• Salicylic acid shampoos: These help to promote the removal of skin flakes, but also cause dryness, which could lead to more flaking.
• Ketoconazole shampoos: These are antifungal shampoos (while they are available over the counter, stronger doses can be prescribed by a healthcare provider in severe cases of dandruff).
• Tar-based shampoos: This type of shampoo is made from coal tar. It also slows the rate of skin cell death, lowering the presence of the resulting skin flakes. Tar-based shampoos can cause discoloration of blond or white hair. This type of medicated shampoo can also make the scalp more sensitive to sunlight.

These medicated shampoos are often recommended for daily use when they are first started. Once dandruff is under control, these shampoos can often be used just once or twice each week. 

If the OTC shampoos don’t alleviate your dandruff symptoms, consult with a healthcare provider about the possible use of a prescription shampoo.

Prognosis 

In adults and adolescents, dandruff cannot be cured. The condition comes and goes throughout a person’s lifetime, but the symptoms can be managed effectively with treatment.

With regular treatment, dandruff is known to improve quickly. If your dandruff symptoms do not respond to an over-the-counter dandruff shampoo, or if affected areas form crusts, drain fluid or pus, or become painful, be sure to consult with your healthcare provider.