Dandruff is a common, non-contagious skin condition that affects the scalp (the skin that covers the top and back of the head) and causes flakes of skin to appear. Non-contagious means that you cannot catch dandruff from someone who has the condition.

Dandruff can vary in severity- it can be mild, moderate or severe.

How does dandruff occur?

Skin cells are constantly renewing themselves. When skin cells on the scalp are renewed, the old ones are pushed to the surface and come away from the scalp.

In people with dandruff, skin renewal is faster, which means that more dead skin is shed and your dandruff is more noticeable.

How common is dandruff?

Mild dandruff can affect anyone, although it tends to affect men more than women. Dandruff often occurs after puberty and is most common in people in their early twenties. Puberty is the period of life when the body reaches sexual maturity and causes physical, psychological and behavioral changes.

Dandruff is uncommon in pre-pubescent children (those who are between two and ten years of age).

Seborrhoeic dermatitis

Seborrhoeic dermatitis is a common, non-infectious skin condition that affects about 3 in 100 people. It is the commonest cause of dandruff and makes the skin become inflamed or flaky.

Seborrhoeic dermatitis is a condition that can affect a number of areas of the body, including:

• the scalp
• the face
• in and around the ears
• the front of the chest and between the shoulder blades
• body folds (flexures)

Seborrhoeic dermatitis of the scalp can be mild, moderate or severe and causes red areas that can sometimes weep and are covered with oily white and yellow scales.

See Dandruff - prevention for more information and advice about how seborrhoeic dermatitis and dandruff can be prevented.

Outlook

Dandruff and seborrhoeic dermatitis are treatable skin conditions that usually respond well to treatments such as medicated shampoos. However, following treatment, dandruff can reoccur at any time. See Dandruff- treatment for more information.

Dandruff

The main symptom of dandruff is white or grey dry flakes of skin on your scalp and in your hair. The flakes are often noticeable if they fall from your scalp on to your shoulders. Your scalp may also feel tight, sore or slightly itchy.

Seborrhoeic dermatitis

Adults

In adults, the symptoms of seborrhoeic dermatitis of the scalp can include:

• an itchy or sore scalp
• a red rash around the scalp, ears or forehead that sometimes weeps
• greasy white or yellow scales that can be accompanied by red patches of skin
• hair loss

Babies and infants

In babies and infants, seborrhoeic dermatitis of the scalp is often referred to as cradle cap. It is a harmless, temporary condition that is not contagious (cannot be passed on to others).

Seborrhoeic dermatitis is most often seen in newborns and infants who are up to six months old. However, it usually resolves itself by the age of 6 to 12 months.
 
The symptoms of seborrhoeic dermatitis are:

• thick, yellow crusts on the scalp
• patches of red scaly skin on the scalp, hairline or forehead

Treatment for seborrhoeic dermatitis is usually not required and the condition can be easily managed using:

• mild baby shampoo
• baby oil
• olive oil
• coconut oil

See the Health A-Z topic about Cradle cap for more information about seborrhoeic dermatitis in babies and young children.

Dandruff

The exact cause of dandruff is unknown, but it is not linked to poor hygiene.

Possible causes of dandruff include:

• a reaction to a type of yeast that lives on the skin called a Malassezia
• hormones, which may be involved because dandruff commonly occurs after puberty
• not brushing your hair regularly, which may lead to dandruff because the dead skin cells are not able to shed properly
• a fungal infection, either of the outer layers of the skin (superficial fungal infection) or the deeper layers of the skin (subcutaneous fungal infection) caused by fungi such as moulds and yeasts
• stress, which is also thought to trigger dandruff or make the symptoms worse

People with dry skin are more likely to be affected by dandruff.

If you have dandruff, your symptoms may improve during warmer months and get worse when it is colder. This is because the ultraviolet (UV) light from the sun is thought to counteract (act against) the yeast on your skin.

Seborrhoeic dermatitis

The cause of seborrhoeic dermatitis is not fully understood. However, it is believed to be caused by the following:

• a reaction to a type of yeast living on the skin called a Malassezia
• genetics (the condition appears to run in families)
• the production of too much oil on the skin

Seborrhoeic dermatitis is also more likely to occur in people with the following conditions:

• Parkinson's disease: a chronic (long-term) neurological condition that is caused by a loss of nerve cells in the brain stroke
• : a serious medical condition that occurs when the blood supply to the brain is disturbed
• HIV: a long-term (chronic) virus that attacks the body's immune system

Seborrhoeic dermatitis is more common in people with these conditions because the yeasts that are thought to cause the condition (Malassezia yeasts) grow more easily in people who are immunocompromised (have a weakened immune system) and those with certain neurological conditions (which affect the nervous system). 

Other factors

Other factors that may increase your risk of developing seborrhoeic dermatitis include:

• an illness that reduces general health
• psychological stress
• fatigue (tiredness)
• change of season
• some medicines (these may induce or make seborrhoeic dermatitis flare up) 

• Dandruff

  Dandruff does not usually need to be formally diagnosed because its symptoms are obvious. The characteristic dry, white flakes on your scalp or in your hair are typical of the condition.

  Seborrhoeic dermatitis

  See your GP if you think you may have seborrhoeic dermatitis. They can diagnose the condition by looking at the red rash on your skin. Tests are not usually required.

  Ruling out other skin conditions

  To confirm a diagnosis of seborrhoeic dermatitis, your GP will examine the redness and colour of the scaling on your scalp.

  This will enable your GP to rule out a different skin condition called psoriasis, which causes red, flaky, crusty patches of skin and silvery scales and has similar symptoms to seborrhoeic dermatitis.

  If your GP thinks that a fungal infection may be present in your scalp (scalp ringworm), a skin sample may be taken and sent away to a laboratory for testing.

  Before using any treatments for dandruff or seborrhoeic dermatitis, get advice from your GP or pharmacist.

  Dandruff treatments aim to slow down the reproduction of skin cells and counteract the yeast production that may be causing the condition.

  If you are pregnant or breastfeeding, check with your GP or pharmacist before you use any treatments for dandruff or seborrhoeic dermatitis.

  A number of different products are available that are effective in treating both dandruff and seborrhoeic dermatitis.

  Medicated shampoos for either dandruff or seborrhoeic dermatitis

  Shampoos and scalp preparations to help treat dandruff and seborrhoeic dermatitis are available over the counter from your local pharmacy and most supermarkets.

  Medicated shampoos (shampoos that contain specific anti-infective and antifungal ingredients to treat conditions affecting the skin and scalp) that contain the ingredients below are effective in treating both skin conditions.

  Zinc pyrithione

  This antifungal treatment reduces the production of yeast.

  Salicylic acid

  This ingredient belongs in a group of medicines called keratolytic agents and helps soften and shed the skin cells on your scalp (although this may make your scalp dryer than before you used the treatment).

  Selenium sulfide

  This is an anti-infective ingredient that relieves itching and flaking of the scalp and removes dry flakes (discuss this with your GP or pharmacist before using it, and do not use on children under two years of age).

  Ketoconazole

  This is often the most effective antifungal ingredient in reducing and shedding cells from the scalp. In severe and persistent cases of dandruff, it may work when other antidandruff shampoos have had little or no effect.

  Shampoos that contain ketoconazole can be used on people of all ages. Ketoconazole works by preventing the growth of the fungi and yeasts. Before using an antifungal shampoo, try to remove any scaly or crusty patches from your scalp. This will improve the shampoo's effectiveness.

  Coal tar

  Products that contain coal tar (a thick, black liquid extracted from coal) are also effective in treating dandruff and seborrhoeic dermatitis. However, there are a number of factors to consider before you decide to use this treatment:

  • Coal tar has an odour that is similar to road tar, which you may find unpleasant.
  • Coal tar can increase your chance of getting sunburnt for up to 24 hours after use.
  • Coal tar should not be used for long periods without consulting your GP.

  Medicated shampoos for dandruff only

  Medicated shampoos that contain the following ingredients are effective in treating dandruff only:

  • sulfur
  • salicylic acid combined with sulfur

  In adults, dandruff often reoccurs after treatment and further treatment may be required. Antidandruff shampoo can also be applied to beards if you have a beard that is affected by dandruff.

  Medicated shampoos for seborrhoeic dermatitis only

  Adults

  Treatment for seborrhoeic dermatitis will help control the skin condition, but will not cure it completely. Treatment may have to be used for months or even years, because seborrhoeic dermatitis often reoccurs and you may experience flare-ups.

  As well as the treatments mentioned above, other treatments are available for tackling severe seborrhoeic dermatitis. Depending on the severity of your condition, your GP may prescribe steroid scalp applications (in the form of lotions and gels). These will help reduce itching and redness.

  Babies and infants

  Seborrhoeic dermatitis in babies (often called cradle cap) usually clears up on its own and treatment is usually not necessary. However, it may take a few weeks, or in some cases a few months, to clear up completely.

  The symptoms of cradle cap can be managed effectively with:

  • mild baby shampoos
  • baby oil
  • olive oil
  • coconut oil

  • It is very unusual for complications to develop as a result of dandruff and seborrhoeic dermatitis.

    The most likely complication is an adverse reaction to any treatments you may be using. If a product irritates your scalp, stop using it immediately. Your GP or pharmacist can recommend a more suitable alternative.

    It is possible for dandruff or seborrhoeic dermatitis to cause an infection if a germ enters a break in your skin or scalp.

    Contact your GP if your dandruff does not improve after using over-the-counter medicated shampoos, or if your scalp becomes swollen and red.

    Also contact your GP if you have seborrhoeic dermatitis that does not respond to treatment, or if you experience any of the following:

    • the patches of seborrhoeic dermatitis contain fluid or pus
    • crusts form on the patches of seborrhoeic dermatitis
    • the patches of seborrhoeic dermatitis become red or very painful

    Although dandruff and seborrhoeic dermatitis are not signs of poor hygiene, they can sometimes cause psychological distress and affect a person's self-esteem.

  • In adults, dandruff and seborrhoeic dermatitis may return at any time.

    There is not much you can do to prevent dandruff and seborrhoeic dermatitis from reoccurring. However, using an antidandruff or antifungal shampoo once a week (or as prescribed on the bottle) after the scalp is clear may help to prevent dandruff and seborrhoeic dermatitis of the scalp.

    Self-care advice

    The following steps can help prevent dandruff:

    • Try not to scratch your scalp when using shampoo. Gently massage your scalp without scratching as this will not damage your scalp or your hair.
    • Brush your hair daily and wash it at least three times a week. After washing your hair, rinse it thoroughly to get all the shampoo out. Using a shampoo that contains tea tree oil daily may help reduce dandruff. It contains an antifungal and antiseptic and can be bought in health shops.
    • Avoid using chemicals on your scalp, such as those used in hair colouring products. The chemicals reduce the number of bacteria on the scalp that are needed to fight against yeasts.
    • Using hair products, such as hair gels and hair sprays, can build up oils and can irritate the scalp in some people. You may want to stop using a product for a while to see if your dandruff improves, or change products completely.
    • Spending time outdoors can help reduce dandruff. However, ultraviolet (UV) light from the sun can damage your skin, as well as increasing your risk of developing skin cancer. Make sure you protect yourself from the sun by using a sun screen with the appropriate skin protection factor (SPF) for your skin type.
    • Managing stress can reduce your risk of getting dandruff. Stress can have an adverse effect on your overall health and can increase your risk of becoming ill. Stress can also trigger dandruff or make existing dandruff worse. If you feel stressed or under pressure, your GP can recommend a variety of different ways to help treat your stress. See the Health A-Z topic onStress for more detailed information.

    See your GP if you are concerned about the location, amount and size of any flakes of dandruff. Your GP may test for other conditions, such as psoriasis (a skin condition that causes red, flaky, crusty patches of skin and silvery scales).