Dandruff: Causes, Treatment and Prevention
Dandruff usually appears as dry white flakes of skin that are shed from the scalp and can be seen on a person’s hairbrush, collar or shoulders. It is a cosmetic problem rather than a health risk. Dandruff is usually painless, normally causes no itching and is not passed on to others. However, its appearance can be unpleasant and embarrassing for the person who has it.
Dandruff is a very common condition that is likely to affect nearly everyone at some point in their lives. It occurs when the normal rate of shedding old scalp cells and their replacement by new cells becomes too rapid. There are a variety of triggers and causes that can include hormones and a fungal infection of the scalp. Even the climate or the time of year can affect dandruff, as it is more frequent in winter.
Dandruff can usually be controlled with over-the-counter treatments including medicated shampoos, rinses, leave-on applications or ointments. However, if the problem persists, a doctor can prescribe a stronger medication. Although many shampoos and medications are effective, there is not one that treats everybody.
People who suffer from dandruff should avoid using alkaline shampoos that can encourage or worsen dandruff and products, such as hair conditioners, wet-look gels or sprays, which make their hair or scalp oilier.
Symptoms of Dandruff
The only real symptom of dandruff is white flakes of dead skin which are shed from the scalp and which are particularly noticeable on a person’s collar, shoulders as well as hairbrush. Dandruff does not usually cause itching or inflammation and is not contagious. However if the scalp is severely inflamed, the patient should see a doctor. This is because it may be a different medical condition that requires a different treatment than those used for dandruff.
Causes of Dandruff
Dandruff occurs when the natural turnover of scalp cells (loss and replacement) becomes too rapid. That is, the cells reach the surface of the scalp abnormally quickly, typically in about a half or a third of the normal time. As a result, dead cells build up in clumps on the patient’s scalp and are shed as noticeable white flakes.
Many cases of dandruff are caused by dry or flaky skin or not shampooing often enough. Another common cause of dandruff is a yeast infection of the scalp. A yeast called Pityrosporum ovale (malassezia) is a type of fungus which we all have on our body and scalp and which normally does us no harm at all. But, sometimes these yeasts multiply more rapidly than usual and irritate the scalp which results in dandruff. In addition, certain skin conditions, such as psoriasis or eczema, can contribute to dandruff or can be confused with dandruff (for more information, see this article).
Seborrheic dermatitis, a medical condition characterized by greasy, irritated scalp and flaky scales, may also cause dandruff. Sometimes, seborrheic dermatitis is considered to be a more severe form of dandruff. This condition can also affect eyebrows, the skin around the nose, the lines on the cheeks, the backs of the ears, forehead and armpits.
Research suggests that there may be a hormonal link to dandruff. It is thought that male sex hormones called androgens could be responsible for greasy or oily skin that may result in dandruff. And in fact, more men suffer from dandruff than women. People are also much more likely to suffer from dandruff after puberty. Furthermore, the climate or the time of year can also affect dandruff as it is more common in winter.
Risk Factors for Dandruff
The following factors may increase the risk of dandruff:
- Age. Dandruff is rare before puberty. It most often occurs in adolescence and late teens, which is probably a result of changes in hormonal activity during that time.
- Alkaline shampoo. Using a shampoo that is too alkaline can make dandruff worse. People who suffer from dandruff should choose a shampoo that has a neutral or slightly acidic pH.
- Climate. Dandruff is more common in cold, dry winters and living in a cold climate can make dandruff worse.
- Gender. Men are more likely to get dandruff than women. This is believed to be due to male hormones androgens.
- Hygiene. Not washing hair often enough can also lead to dandruff or make it worse. Poor hygiene is more likely to encourage the build-up of a fungus called Pityrosporum ovale (malassezia) on the scalp and its overgrowth causes dandruff.
- Oily hair. People with oily skin and hair are more likely to get dandruff than people with normal skin. Androgen hormones may also be the cause of greasy or oily skin which in turn results in dandruff. Oily, greasy hair is associated with yeast infections (malassezia) in the scalp, which are known to cause dandruff.
- Stress. Dandruff can be triggered or made worse by stress.
- Sweating. Dandruff is more common in people who sweat a lot because sweating can make hair oilier and make fungal infections more likely.
Treatments for Dandruff
It is often possible to effectively control dandruff by using a medicated shampoo, such as Head & Shoulders, Neutrogena T/Gel, Selsun Salon, Redken Dandruff, Nizoral, etc., which are available over-the-counter in most pharmacies. Most commonly, these shampoos require the patient to wash their hair every day and thoroughly massage their scalp.
The shampoo should be used as directed for several weeks (as it usually takes some time for the normal cells in the scalp to replenish), unless there is an adverse reaction. If there is no improvement after several weeks of using one product, it may help to try a different brand that contains different active ingredients. Once the dandruff is under control, it is often recommended to rotate different shampoos that have been shown to work.
If dandruff is still present despite using two or more medicated shampoos correctly for several weeks, it is best to consult a doctor or a skin specialist (dermatologist). This is especially important if there is redness, itching and/or loose dry scales of dead skin on the scalp or any other skin problems elsewhere on the body.
The doctor will examine the patient’s scalp and may prescribe an ointment, cream, shampoo or lotion to use on the scalp. Very rarely, a patient with particularly stubborn dandruff or dandruff associated with another skin condition may need to take pills to clear up the condition. A shampoo or lotion prescribed by the doctor will usually contain one or more of the following ingredients:
- Caffeine (found in Alpecin)
- Coal tar (found in Caposal, Cinitar, Cocois, Denorex, Gelcotar, Ionil T, Neutrogena T/Gel, Pentrax, Polytar, Tegrin and Zetar)
- Salicylic acid (found in Caposal, Ionil T, Meted and Sebulex)
- Selenium sulfide (found in Selsun blue)
- Sulfur (present in many different shampoos, such as Meted or Sebulex, and most commonly found together with other anti-dandruff ingredients)
- Zinc pyrithione (found in Caposal, DHS Zinc Shampoo, Head & Shoulders, Meted, Selsun Salon and ZNP)
In addition to the above treatments, several home remedies have been shown to help with dandruff. These include tea tree oil, apple cider vinegar, baking soda, curd, lemon, neem (Indian lilac), and olive and coconut oils.
In order to prevent dandruff in normal hair and scalp, people should:
- Avoid using oily scalp or hair products or products that make their scalp oilier
- Wash their hair regularly (once or twice a week)
- Rinse hair products out thoroughly to prevent them irritating their scalp
In addition to the above tips, patients should use a medicated shampoo once or twice a week to prevent dandruff from coming back once it has cleared up. They should also massage their scalp regularly, either before or while washing their hair.
Where to Find More Information: American Academy of Dermatology