Dandruff - Lloydspharmacy.com Health

Reviewed by Dr Stuart Crisp, consultant paediatrician

What is dandruff?

Your skin constantly renews itself; dead cells from the scalp fall off as new cells form beneath them. Everyone loses skin cells in this way.

With dandruff the process is faster, so a greater number of cells are shed. This means the cells shed in clumps (flakes) that are big enough to be seen by the eye.

Flakes of dandruff are especially visible when they land on dark clothing. The scalp can also be itchy. The medical name for dandruff is pityriasis capitis, and it's the most common condition of the scalp.

Many people think they get dandruff because their scalp's too dry. They stop washing their hair with shampoo, or wash it less frequently, because they believe it makes the condition worse. This isn't true.

Flaking only happens because of an increased turnover of skin cells or an infection of the scalp. It's more common in children with eczema.

Dandruff is believed to be associated with an overgrowth of a fungus commonly found on the skin and scalp, called Malassezia (previously called Pityrosporum ovale).

Can dandruff be prevented?

It can be difficult to prevent dandruff completely, but it can be controlled. The condition may also improve as you get older.

How is dandruff treated?

Anti-dandruff shampoo

Anti-dandruff shampoos, containing the antimicrobials selenium sulphide (eg Selsun) or zinc pyrithione (eg Polytar AF), are helpful for mild dandruff.

They are widely available and are also active against the fungus Malassezia.

Antifungal shampoo

Antifungal shampoo containing ketoconazole provides a mild, yet effective, treatment for dandruff.

It's good for persistent or severe dandruff and also stops Malassezia.

Brands include Nizoral and Dandrazol and can be bought from supermarkets, as well as pharmacies.

It should be used twice weekly for two to four weeks to clear the dandruff.

After that, you should use it every one to two weeks to prevent dandruff coming back.

What if the dandruff doesn't respond to treatment?

You should see your GP if:

your dandruff persists, despite using the above shampoos
your dandruff gets more severe
scaling also affects other parts of the body.

It may be your dandruff is due to other skin conditions – such as seborrhoeic dermatitis, eczema or psoriasis.

Your GP can then refer you to a dermatologist or skin specialist.

Seborrhoeic dermatitis

Sun kind?

Sunlight, including artificial sunlight from sun-beds, can improve seborrhoeic dermatitis.

But too much sunlight may cause wrinkles and even skin cancer.

Severe cases of dandruff are caused by a disease, called seborrhoeic eczema or seborrhoeic dermatitis, that causes greasy bran-like scale.

The seborrhoeic area may also be red and itchy – that's your eyebrows, ears, scalp, the skin around your nose, the lines on your cheeks and your torso.

Seborrhoeic dermatitis becomes worse in winter and tends to improve during the summer, when sunlight relieves the symptoms.

It can vary from mild cases, which are only a problem in winter, to more severe cases – where flaking occurs in places other than just the scalp.

The fungus Malassezia is a significant factor in seborrhoeic dermatitis. Doctors don't know exactly why, but anti-fungal treatment (ketoconazole shampoo) helps ease the condition.

Stress and serious illnesses can also cause an increase in the production of scale.

A sudden, strong tendency to flaking or seborrhoeic dermatitis in a middle-aged person, who has never had such problems before, can be a sign of HIV infection.

Based on a text by Dr Flemming Andersen

Last updated 12.05.2010

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