What is dandruff?
Dandruff is a common condition that affects the scalp, causing excessive shedding of skin flakes.
The skin flakes stick to the hair shafts, where they may accumulate oil, dust and hair products. These flakes eventually fall on the collars and shoulders of clothes.
Symptoms of dandruff
Dandruff symptoms include:
- white scales and flakes on the scalp or in the hair, which may fall onto the shoulders;
- itching or scalp irritation; and
- a scaly scalp.
Dandruff or dry skin?
It can sometimes be hard to tell the difference between dry skin affecting the scalp and dandruff.
In general, dandruff scales are large and oily, and the scalp can be red and inflamed. Dry skin usually results in small, white flakes of skin without any obvious skin inflammation. Dry skin also tends to affect other areas of skin, such as the legs and arms, as well as the scalp.
Causes of dandruff
Dandruff is due to an overproduction of skin cells and shedding of dead skin from the scalp.
Your skin normally sheds layers of cells continuously, and your scalp sheds more skin cells than other parts of the body. Dandruff is when an excessive amount of larger-than-normal flakes of scalp skin are shed.
Dandruff can be due to seborrhoeic dermatitis - a skin condition that causes the scalp to shed skin cells more than is normal. Seborrhoeic dermatitis results in an oily scalp plus a red, scaly, itchy rash. Areas other than the scalp (such as the cheeks, nose and eyebrows) can also be affected.
A contributing cause of seborrhoeic dermatitis is overgrowth of a type of yeast known as Malassezia. Malassezia yeasts live on most healthy scalps without causing problems, but can cause dandruff when they grow out of control.
Psoriasis and atopic dermatitis (eczema) are other skin conditions that can cause dandruff when they affect the scalp.
Dandruff is not a contagious condition – it cannot be passed from one person to another.
Risk factors for dandruff
Risk factors for developing dandruff may include:
- washing your hair too often or not washing it often enough;
- overuse of hair products;
- cold weather (because indoor heating tends to dry the skin and scalp); and
Dandruff tends to also affect people with certain neurological conditions such as Parkinson’s disease (it is not known why), as well as people with problems with their immune systems.
Can dandruff be cured?
There is no cure for dandruff, but with trial and error you should be able to find the best ways to look after your scalp and the best types of dandruff products to manage any exacerbations you have.
The initial treatment for dandruff often involves using a regular shampoo once a day until the scalp is clear. Rinse your hair well to eliminate any build-up of hair products. Many people find that regular washing is beneficial; however, some people may find their scalp is irritated by this.
If regular shampoo is not effective, there are several types of anti-dandruff shampoo available from pharmacies to help treat dandruff.
There are several types of anti-dandruff shampoos available in Australia. You can buy these from the pharmacy without a prescription.
Medicated shampoos that can be used to treat dandruff include those containing the following.
- Ciclopirox olamine, e.g. Stieprox Liquid (Shampoo), an anti-yeast shampoo that can stop the growth of Malassezia, and can also reduce inflammation.
- Zinc pyrithione, which is an anti-yeast shampoo that also slows down the production of skin cells.
- Selenium sulfide (e.g. Selsun Blue) slows the production of skin cells and has anti-fungal properties.
- Coal tar (e.g. Neutrogena T/Gel Therapeutic Shampoo) slows down the speed that scalp cells die and flake off.
- Ketoconazole (e.g. Nizoral Shampoo) and miconazole (e.g. HairScience for Dandruff Shampoo) are broad-spectrum, powerful antifungals that inhibit the growth of yeast and other fungal infections.
Make sure you read the instructions before using any medicated shampoos, and check with your pharmacist whether the product is suitable for you and your hair type.
Sometimes a shampoo will control dandruff for a while but then become less effective. It can help to change to a different type of anti-dandruff shampoo.
Shampoos containing antifungal agents often need several applications per use and should be massaged into the scalp and left in the hair for several minutes. Be careful not to get the shampoo in your eyes. If you do, rinse out your eye immediately with clean water.
When using coal tar-based products it is important to use the accompanying rinse or conditioner as this helps remove the coal tar smell. You should also avoid strong sunlight, as your scalp may be more susceptible to sunburn.
As products containing coal tar and selenium sulfide may stain, you should ensure that the shampoo is thoroughly rinsed away.
Keratolytic agents such as salicylic acid loosen keratin in the outer skin cells. As the cells loosen they are discarded, exposing the new skin underneath.
Keratolytic shampoos are available from pharmacies.
In people with scalp seborrhoeic dermatitis that is not controlled with medicated shampoo alone, or in people with a very itchy scalp, occasional applications of a topical corticosteroid may help.
Corticosteroid lotions that may be prescribed include:
- betamethasone (e.g. Diprosone lotion);
- methylprednisolone (brand name Advantan); or
- mometasone lotion (brand names Elocon, Novasone, Zatamil).
A coal tar emulsion, gel or cream may need to be added if the above treatments are not controlling scalp seborrhoeic dermatitis.
Coal tar preparations are applied to the scalp in the evening and washed off in the morning with an anti-yeast shampoo. This is usually recommended once or twice a week.
Self-care and home remedies
There are some simple self-care measures and remedies you can take to help treat and prevent dandruff.
- Massage your scalp for a few minutes each day to stimulate the circulation and loosen dead skin cells. This can then be followed by brushing to remove loosened flakes.
- Oily hair can often benefit from rinsing with fresh lemon juice or apple cider vinegar diluted in water.
- A dry scalp may benefit from a warm oil treatment used once a week. Massage olive oil into your hair and scalp and warm in a hot towel for at least 10 minutes (preferably a few hours) before washing.
- Tea tree oil has anti-fungal properties and tea tree shampoo has been shown to help in the treatment of dandruff.
- Supplements that may help control dandruff include flaxseed oil and zinc.
- Avoid excessive use of hair products (including dyes) and change shampoo if one brand is not proving effective. An allergy-free product may work better for you.
- Stress and negative emotions have been known to play a part in skin conditions such as dandruff, so relaxation techniques may be helpful.
When to see your doctor
Severe, persistent dandruff may be a symptom of a skin condition such as eczema, psoriasis or seborrhoeic dermatitis, and you should consult your doctor.
Sometimes severe dandruff associated with seborrhoeic dermatitis can cause thinning of the hair. Fortunately, in most cases the hair should grow back once the condition is treated.
If you have persistent problems with dandruff or complications of it, your doctor may refer you to a dermatologist – a specialist doctor who deals with skin and hair problems.
2. DermNet NZ. Seborrhoeic dermatitis (updated Jul 2014). http://www.dermnetnz.org/dermatitis/seborrhoeic-dermatitis.html (accessed Jul 2016).
3. Mayo Clinic. Dandruff (updated 14 Jul 2016). http://www.mayoclinic.org/diseases-conditions/dandruff/home/ovc-20215279 (accessed Jul 2016).