What Causes Dandruff?

Is your scalp itchy? Do small, white flakes show up on your scalp and fall to your shoulders every time you shake your head? If so, you likely have dandruff.

Dandruff is a common yet embarrassing scalp condition that can be incredibly frustrating to treat. It’s notoriously difficult to get rid of because there are several different factors that can potentially trigger the condition.

However, don’t let this discourage you from finding a treatment for your dandruff. Once you understand the underlying causes of dandruff, you can choose the best treatment option that will get rid of white flakes for good.

Here are three things you need to know about dandruff:

• Dandruff can be caused by Malassezia, a small yeast that lives on human skin.
• Other causes of dandruff may include seborrheic dermatitis and scalp psoriasis.
• Factors such as diet, stress and genetics can make dandruff symptoms worse.

While dandruff can be incredibly frustrating, that doesn’t mean it’s impossible to treat. Below, we’ll discuss what causes dandruff and provide a few tips for getting rid of it.

What Is Dandruff?

There are many skin conditions that affect the scalp, dandruff being one of the most common. This annoying yet benign condition of the scalp produces white flakes of dead skin to appear in your hair.

Human skin naturally replaces itself by producing new skin cells and shedding old ones. According to the American Skin Association, this skin shedding cycle takes roughly 28 days to complete.

In those who have dandruff, this skin cell production cycle is increased. As a result, skin cells are shed faster and with more oil, which causes them to stick together in noticeable clumps.

What Causes Dandruff?

Contrary to popular belief, dandruff is not always caused by dry skin. In fact, waiting too long to wash your hair could be making the problem worse.

Here are the most common causes of dandruff:

1. Seborrheic Dermatitis

If your dandruff is accompanied by red, irritated skin, it may be caused by a skin condition called seborrheic dermatitis (SD). This inflammatory skin condition is characterized by red, scaly patches of skin that affect the oiliest areas of the body, such as the face, nose, scalp and ears.

People with SD may notice flare-ups when the weather becomes cold and dry. Fortunately, you can usually treat SD-related dandruff by using a dandruff shampoo for men, while treating the rest of your skin with a topical, anti-fungal cream.

2. Malassezia

Not to gross you out, but our skin is densely populated by fungi. While many fungal species are relatively harmless—such as dandruff-causing Malassezia—they can become a problem if our body’s immune system doesn’t keep them in check.

Malassezia is a small yeast that lives on the skin and appears to thrive off oily and moist areas of the skin. According to a 2015 study published in the Indian Journal of Dermatology, Malassezia is most commonly found in young adults, a population which tends to have oily skin (see claim: “It is seen in higher densities in young adults, who tend to have relatively oily skin.”)

Scientists argue that Malassezia fungi play an important role in your skin’s microbiome, which is why you don’t want to completely eradicate it (see claim: “Malassezia yeasts are integral components of the skin microbiota...”) However, you can help control it by not going as long between shampooing your hair and using a dandruff shampoo.

3. Scalp Psoriasis

Scalp psoriasis can also cause dandruff-like flakes. However, it looks slightly different.

Psoriasis is a chronic skin condition that causes thick, scaly plaques of skin—most commonly on the elbows and knees. If you have a flaky scalp and struggle with psoriasis elsewhere on the body, your dandruff is likely scalp psoriasis.

Medicated shampoos are often the first line of treatment for scalp psoriasis. If you don’t already see a dermatologist for your skin condition, consider scheduling an appointment to discuss treatment options.

4. Diet, Stress and Genetics

Although not a direct cause of dandruff, factors such as diet, stress and genetics can make the condition worse. For instance, stress can weaken your body’s immune system, which plays a key role in fighting off dandruff-causing Malassezia.

Your diet can also contribute to dandruff by stimulating hormones that increase your skin’s oil production and allow Malassezia to thrive. According to a 2018 study published in the Journal of the Academy of Nutrition and Dietetics, high-glycemic foods were shown to increase insulin-like growth factor 1, which is believed to play a role in the initiation of sebum production (see claim: “GF-1 concentrations decreased significantly among participants randomized to a low GI and GL diet between pre- and postintervention time points (preintervention=267.3±85.6 mg/mL, postintervention=244.5±78.7 ng/mL) (P=0.049).”)

Lastly, genetics play a big role in determining your skin type and your immune system. If you have oily skin and a weakened immune system, it stands to reason that Malassezia may have an easier time colonizing on your scalp.

Final Thoughts

Although dandruff can be a tough condition to treat, it’s far from impossible. Once you know the underlying conditions, you can take the right steps to get rid of it for good.

The key is to be patient and allow your dandruff treatments to do their job. Just like your acne treatment system, dandruff treatments don’t work magic overnight. With the right approach and plenty of patience, your scalp will be healthy and flake-free in no time.

References

Healthy Skin  |  American Skin Association. http://www.americanskin.org/resource/. Accessed 24 Sept. 2019.

Thayikkannu, Ambujavalli Balakrishnan, et al. “Malassezia—Can It Be Ignored?” Indian Journal of Dermatology, vol. 60, no. 4, 2015, pp. 332–39. PubMed Central, doi:10.4103/0019-5154.160475.

PLOS. "Malassezia yeasts, everywhere and sometimes dangerous." ScienceDaily. ScienceDaily, 8 January 2015. 

Burris, Jennifer, et al. “A Low Glycemic Index and Glycemic Load Diet Decreases Insulin-like Growth Factor-1 among Adults with Moderate and Severe Acne: A Short-Duration, 2-Week Randomized Controlled Trial.” Journal of the Academy of Nutrition and Dietetics, vol. 118, no. 10, 2018, pp. 1874–85. PubMed, doi:10.1016/j.jand.2018.02.009.