Dandruff involves flakes of skin that collect in the hair.
The exact cause is unknown, but various factors increase the risk. It is not related to poor hygiene, but it may be more visible if a person does not wash or brush their hair often.
Dandruff can be embarrassing and hard to treat, but help is available.
Here are some key points about dandruff. More detail is the main article.
- Dandruff is a common condition, but it can be embarrassing and difficult to treat.
- It is not related to hygiene, but washing and brushing the hair can help remove old skin flakes.
- Risk factors include having certain skin or medical conditions and the use of inappropriate hair products.
- Various treatments are available over the counter, but more severe cases should be seen by a doctor.
The exact causes of dandruff are unknown.
One theory is that it is linked to hormone production, as it often begins around the time of puberty.
Here we look at 10 more possible factors.
1. Seborrheic dermatitis
People with seborrheic dermatitis have irritated, oily skin, and they are more likely to have dandruff.
Seborrheic dermatitis affects many areas of the skin, including the backs of the ears, the breastbone, eyebrows, and the sides of the nose.
The skin will be red, greasy, and covered with flaky white or yellow scales.
Seborrheic dermatitis is closely linked with Malassezia, a fungus that normally lives on the scalp and feeds on the oils that the hair follicles secrete.
It does not usually cause a problem, but in some people it becomes overactive, causing the scalp to become irritated and to produce extra skin cells.
As these extra skin cells die and fall off, they mix with the oil from the hair and scalp, forming dandruff.
2. Not enough hair brushing
Combing or brushing the hair regularly reduces the risk of dandruff, because it aids in the normal shedding of skin.
People who are sensitive to yeast have a slightly higher chance of dandruff, so yeast may play a part. Dandruff is often worse during the winter months and better when the weather is warmer.
This may be because ultraviolet-A (UVA) light from the sun counteracts the yeast.
4. Dry skin
People with dry skin are more likely to have dandruff. Cold winter air combined with overheated rooms is a common cause of itchy, flaking skin. Dandruff that stems from dry skin tends to have smaller, non-oily flakes.
5. Shampooing and skin care products
Certain hair care products can trigger a red, itchy, scaling scalp. Frequent shampooing may cause dandruff, as it can irritate the scalp.
Some people say not shampooing enough can cause a buildup of oil and dead skin cells, leading to dandruff, but evidence is lacking that this is true.
6. Certain skin conditions
7. Medical conditions
Not consuming enough foods that contain zinc, B vitamins, and some types of fats may increase the risk.
9. Mental stress
There may be a link between stress and many skin problems.
Dandruff is more likely from adolescence through middle age, although it can be lifelong. It affects men more than women, possibly for reasons related to hormones.
Treatment aims to stop the dandruff by slowing down the reproduction of skin cells or counteracting the yeast production that might be the cause.
The strategy will depend the patient's age and the severity of the condition.
Shampoos and scalp preparations
Shampoos and scalp products are available over the counter at most stores and pharmacies. These can control seborrheic dermatitis, but they cannot cure it.
Before using an anti-fungal shampoo, individuals should carefully try to remove any scaly or crusty patches on the scalp, as far as possible, This will make the shampoo more effective.
Dandruff shampoo is available to treat dandruff in the beard.
Ingredients to look out for
Most anti-dandruff or anti-fungal shampoos contain at least one of the following active ingredients:
- Ketoconazole: An effective anti-fungal. Shampoos containing this ingredient can be used at any age.
- Selenium sulfide: This reduces the production of natural oils by glands in the scalp. It is effective at treating dandruff.
- Zinc pyrithione: This slows down the growth of yeast.
- Coal tar: This has a natural anti-fungal agent. Dyed or treated hair may become stained by long-term usage. Tar soaps may also make the scalp more sensitive to sunlight, so users should wear a hat when outside. Coal tar can also be carcinogenic in high doses.
- Salicylic acids: These help the scalp get rid of skin cells. They do not slow down the reproduction of skin cells. Many "scalp scrubs" contain salicylic acids. Treatment can sometimes leave the scalp dry and make skin flaking worse.
- Tea-tree oil: Derived from the Australian Tea Tree (Melaleuca alternifolia), many shampoos now include this ingredient. It has long been used as an anti-fungal, an antibiotic, and an antiseptic. Some people are allergic to it.
The best strategy is to select a shampoo containing one of these ingredients and shampoo the hair every day until the dandruff is under control.
After this, they can be used less frequently.
Alternating dandruff shampoo with regular shampoo may help. A specific shampoo may stop being as effective after some time. At this point, it may be a good idea to switch to one with another ingredient.
Some shampoos should be left on the scalp for around 5 minutes, as rinsing too quickly will not give the ingredient time to work. Others should be rinsed at once. Users should follow the instructions on the container.
When to see a doctor
More severe cases may indicate a skin condition and should be seen by a doctor.
It is not normally necessary to consult a doctor with dandruff or seborrheic dermatitis, but sometimes dandruff can be a sign of a more serious medical condition.
Medical help should be sought if:
- there are signs of infection, such as redness, tenderness, or swelling
- dandruff is very severe, or it persists after home treatment
- there are signs of eczema, psoriasis, or another skin condition the scalp is very itchy
Complications are rare with dandruff, but they may result from one of the treatments.
If a shampoo or scalp treatment causes irritation, the individual should cease using it and ask a pharmacist to suggest another one.
A person with a weakened immune system, for example, due to HIV or AIDS, should ask their doctor about any dandruff.
Dandruff in babies
Cradle cap is a kind of dandruff that affects newborns and young infants.
Newborns and young infants often have a kind of dandruff known as cradle cap. There will be yellow, greasy, scaly patches on the scalp.
It often appears within the first 2 months after birth and lasts a few weeks or months.
Gently washing with baby shampoo and applying baby oil can help prevent the scales from building up.
If there are signs of skin cracking or infection, if itching, swelling or bleeding occur, or if it spreads to other parts of the body, it is important to see a doctor.
New solutions for dandruff?Research into ways to help people with psoriasis and other skin conditions is ongoing.
Green tea has shown potential for the treatment of dandruff and psoriasis, according to research published in 2012. Researchers believe a special formulation that can penetrate the skin's waterproof barrier will combat excessive cell growth, oxidative stress, and inflammation.
A study carried out by European researchers has suggested that the addition of llama antibodies to shampoo could be a new strategy for fighting dandruff.