The exact cause of dandruff, also known as scurf or Pityriasis simplex capillitii, is unknown. However, most experts agree that dandruff is not caused by poor hygiene.
Dandruff is a condition of the scalp that causes flakes of skin to appear and is often accompanied by itching. In some cases, it can be embarrassing and not easy to treat.
In this article, we look at the possible causes of dandruff and potential treatment options.
Fast facts on dandruff
Here are some key points about dandruff. More detail and supporting information is in the main article.
- A significant number of people with dandruff find it improves as they get older
- It is estimated that about 50 percent of people in Western Europe and North America suffer from dandruff
- Dandruff is more common in men than in women, and in people with oily skin
- Some studies have suggested that diets that are too salty, sugary, or spicy and accompanied by excessive alcohol may exacerbate dandruff
Causes of dandruff
About 50 percent of people in Western Europe and North America suffer from dandruff.
The following are factors that may contribute to dandruff:
1) Seborrheic dermatitis (irritated, oily skin)
People with seborrheic dermatitis are very prone to 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 patient will have red, greasy skin covered with flaky white or yellow scales.
Seborrheic dermatitis is closely linked with Malassezia, a fungus that lives on everybody's scalp and feeds on the oils that our hair follicles secrete. Generally it will cause no problems at all. However, it can grow out of control.
When this happens, the scalp can become irritated and produce extra skin cells. These extra skin cells die and fall off; they mix with the oil from the hair and scalp and turn into what we see as dandruff.
2) Not enough hair brushing
People who do not comb or brush their hair regularly have a slightly higher risk of having dandruff - this is because they are not aiding the shedding of skin that combing or brushing provides.
People who are sensitive to yeast have a slightly higher risk of having dandruff, so it is logical to assume that yeast may play a part. Yeast-sensitive people who get dandruff often find that it gets better during the warmer months and worse during the winter.
UVA light from the sun counteracts the yeast. Some believe that, during the winter, the skin is drier because of exposure to extreme temperatures - hot rooms and the cold air outside - making dandruff more likely.
4) Dry skin
People with dry skin tend to get dandruff more often. Winter cold air, combined with overheated rooms is a common cause of itchy, flaking skin. People with dandruff caused by dry skin tend to have small flakes of dandruff; the flakes are not oily.
5) Not enough shampooing
Some people say that if an individual does not shampoo enough, there can be a buildup of oil and dead skin cells, causing dandruff. However, many experts doubt this is true.
6) Certain skin conditions
People with psoriasis, eczema, and some other skin disorders tend to get dandruff more frequently than other people.
7) Some illnesses
Adults with Parkinson's disease and some other neurological illnesses are more prone to having dandruff and seborrheic dermatitis.
Patients recovering from heart attacks and strokes and some people with weak immune systems may also have dandruff more often than other people.
8) Reaction to hair or skin care products
Some people react to certain hair care products with a red, itchy, scaling scalp. Many experts say that shampooing too often may cause dandruff as it can irritate the scalp.
Some experts say that people who do not consume enough foods that contain zinc, B vitamins, and some types of fats are more prone to dandruff.
10) Mental stress
Experts believe there may be a link between stress and many skin problems.
One study found that 10.6 percent of people with HIV have seborrheic dermatitis.
Treatments for dandruff
Two factors should be considered when you treat dandruff:
- Severity of the dandruff
The aim is to stop the dandruff by slowing down the reproduction of skin cells, or counteract the yeast production that might be the cause.
Shampoos and scalp preparations
Shampoos and products for the scalp are available OTC at most stores and pharmacies. It is important to remember that seborrheic dermatitis can be controlled, but not cured with these products.
Before using an anti-fungal shampoo, individuals should carefully try to remove any scaly or crusty patches on the scalp. If they can be removed, the shampoo will be more effective.
If dandruff is present in the beard, dandruff shampoo can be used on it.
Most anti-dandruff or anti-fungal shampoos contain at least one of the following active ingredients:
- Ketoconazole - a very effective anti-fungal. Most people who use this are pleased with the results. Shampoos containing ketoconazole can be used by people of any age.
- Selenium sulfide - this reduces the production of natural oils by glands in the scalp. It is also very effective at treating dandruff.
- Zinc pyrithione - an ingredient which slows down the growth of yeast.
- Coal tar - this has a natural anti-fungal agent. If hair is dyed or treated, long-term coal tar usage can stain the hair.
- Salicylic acids - these help the scalp to get rid of skin cells. They do not slow down the reproduction of skin cells. Many "scalp scrubs" contain salicylic acids. Some people find salicylic acid treatments leave the scalp dry and eventually make the flaking of the skin worse.
- Tea-tree oil - this oil comes from the Australian Tea Tree (Melaleuca alternifolia). A growing number of shampoos now include tea-tree oil as an ingredient. It has been used for centuries as an anti-fungal, antibiotic, and an antiseptic. However, some people are allergic to it.
- Green Tea potential - Researchers from the Medical College of Georgia found that green tea shows potential for the treatment of dandruff and psoriasis.
Ideally, individuals should select a shampoo that has one of the above ingredients and shampoo their hair every day until the dandruff is under control. When this happens, they can be used less frequently. A particular shampoo may stop being as effective after long-term use; if this occurs, it is a good idea to switch to one that includes another of the above ingredients.
The shampoo should be left on the scalp for around 5 minutes. If it is rinsed off too quickly, the ingredient will not have enough time to work.
If after several weeks dandruff is still a problem, a visit to the doctor or dermatologist (skin specialist) is recommended.
A study carried out by European researchers suggested that the addition of llama antibodies to shampoo could be a new strategy for fighting dandruff.
Possible complications of dandruff
A person with dandruff or seborrheic dermatitis will hardly ever experience complications. If one were to occur, it would more likely be caused by one of the dandruff treatments. If a dandruff shampoo or scalp treatment is causing irritation, the individual should cease using it and ask a pharmacist to suggest another one.
In some cases, bacteria can get under the skin if there is a break in the skin of the scalp. If this happens, and causes illness, or if an area of skin is red, tender, and swollen, a doctor should be consulted.