Everything You Need to Know About Dandruff

I’ve kept Head & Shoulders in my haircare rotation since high school. It’s not something I use every day, but it’s what I fall back on whenever I notice tiny flakes upon parting my hair after a shower. It works well enough, but I’ve never really understood why I got dandruff in the first place, nor whether simply “keeping it at bay” was the right approach. According to the National Institute of Health, I’m not alone: nearly half of adults suffer from some form of dandruff.

If you count yourself among those numbers and, like me, have been dealing with it quietly and to mixed results, read on for the official expert-consulted rundown.

What even is dandruff?

Dr. Debra Jaliman, board-certified dermatologist and Assistant Professor of Dermatology at New York’s Icahn School of Medicine at Mount Sinai, says dandruff happens when the skin isn’t exfoliating properly and dead skin gets stuck on the scalp and begins to flake and itch.

“It can be genetic or environmental,” Jaliman says, but has nothing to do with poor hygiene! “It’s a real skin condition. However, it’s very treatable so nothing to worry about.”

Dandruff is the common name for seborrheic dermatitis on the scalp, a condition that causes red, flaky and itchy skin as a result of too much yeast that’s present on oily areas of the skin. The only difference is that dandruff is restricted to the scalp, while seborrheic dermatitis can affect other areas, like the T-zone, and often causes inflammation. “It’s characterized by fine greasy, flaky scale that is often accompanied by itch and underlying skin redness,” says dermatologist Shereene Idriss of Union Square Laser Dermatology.

What causes it?

Here’s how it works: A yeast-like fungus called malassezia globosa feeds on your scalp oils, says Rebecca Lee, a nurse and founder of the natural health resource, “As these fungi feed on the oils by using enzymes, it creates oleic acid which seeps into the scalp and causes your skin to shed.”

In other words, it’s not caused by dry skin, too much or too little oil, or the frequency of your showers. In fact, researchers are still not completely sure what causes dandruff or seborrheic dermatitis. “Although the exact cause is still unknown, [seborrheic dermatitis] is believed to be an abnormal immune response to a very common yeast that goes unnoticed on most people, called Pityrosporum,” Idriss says.

A note about dandruff: A flaky scalp does not necessary mean dandruff. Flakiness not related to seborrheic dermatitis can also be psoriasis, fungal infections of the scalp or eczema.

Why treat it?

If it’s so common, why do we need to treat it at all? Well, other than the embarrassing fact that it makes us want to constantly scratch our heads and that it can be noticeable when wearing your favorite dark-colored T-shirt, “there is no definitive cure for dandruff. It is a long-term, chronic condition that will come and go over time,” Idriss says. This is why it’s important to know the signs of dandruff and how to treat it properly.

Additionally, Lee says, dandruff can actually block the hair follicles and prevent new hairs from growing, causing thinning.

How do you treat it?

Medicated shampoo

While shampooing regularly can help to reduce symptoms of dandruff, it won’t really solve the underlying problems or eliminate the flakes altogether. That’s why there’s a massive market for dandruff shampoos — people spend about $300 million each year on dandruff treatment products.

Look for shampoos that contain zinc pyrithione, selenium disulfide, sulfur, salicylic acid, ketoconazole and tar. Jaliman says they are all ingredients known to be effective against dandruff and flaky scalps. (Zinc pyrithione is the key ingredient in Head & Shoulders, which is why it works.)

Idriss says she usually recommends patients start with Nizoral shampoo, as it contains 1% ketoconazole, an ingredient that’s a notch below the prescription-strength antifungal that is usually prescribed. “Alternating this with either selenium sulfide shampoo, such as Selsun Blue, or tar shampoos, such as Neutrogena T/Gel, will improve the efficacy over time,” she says. (Be aware that you can’t use tar shampoos if you have blonde hair as it can cause discoloration.)

Dr. Cynthia Bailey recommends a 2% pyrithione zinc treatment, like her Foaming Zinc Cleanser that can be used on the scalp and body. Before shampooing, try applying warm coconut oil for 30 minutes to remove thick buildup. Then massage your shampoo into your scalp. Adds Idriss: If your dandruff is thicker and sticks to your scalp, shampoos with salicylic acid, like Neutrogena T/sal, can help loosen up thick buildup to make it easier to treat the actual yeast below.

Wash often

If you don’t want to use one of these ingredients, “shampooing daily helps even without medicated shampoos,” Bailey says. At the very least, try washing at least every other day, leaving the shampoo on your scalp for five minutes. These steps are particularly important during the winter, because cold weather can worsen seborrheic dermatitis can worsen, causing more dandruff, Idriss says.

At-home treatments

Lee, a proponent of natural remedies, says you there’s also a range of at-home treatment options. Raw honey, for example, “is great for hair growth and getting rid of dandruff… One study shows relief from itchiness, scaling, skin lesions and dandruff within two weeks. Participants were asked to rub diluted honey onto their scalp daily for three hours. After two weeks, maintenance was only needed once a week.”

Apple cider vinegar, which balances the pH of your scalp, can also be used. The pH neutralization makes it hard for yeast infections, bacteria and other fungi to grow.

Idriss notes natural, at-home remedies aren’t always more cost-effective since there are many, many drugstore options now available.

When is it time to see a doctor?

“Try using a few different home remedies (shampoos, masks, exfoliants, essential oils) before visiting a dermatologist,” Lee says. But if you’ve used a few different products, including over-the-counter medicated shampoos, for months without seeing any improvements (or if you happen to notice redness, swelling, a bleeding scalp or sudden hair loss), it’s time to make an appointment. A dermatologist can help you pinpoint the underlying cause of your dandruff and prescribe a more effective treatment.

Tips for maintaining a healthy scalp

Dandruff shouldn’t be the only reason to pay attention to your scalp health. “A healthy scalp is one that is not neglected. Daily hair brushing, starting from the roots and scalp, is essential to promote healthy scalp circulation,” Idriss says.

She recommends washing your hair at least two or three times a week in order to avoid oil and product buildup. When you wash, massage your scalp, and be sure to limit conditioner to the tips of your hair. “If you do have dandruff and are losing hair, it’s important that you not fear washing your hair. It is normal to lose up to 100 hairs a day, so don’t fret if you notice hair on the floor of your tub after washing,” Idriss says.

Lee also recommends using a clarifying shampoo once a month and eating lots of protein from healthy sources, like eggs, salmon, beef, shrimp, pumpkin seeds and cottage cheese.

Do you suffer from dandruff? What has or hasn’t worked?

Illustrations by Amber Vittoria; follow her on Instagram @amber_vittoria.

Julissa Treviño

Julissa Treviño is a writer and journalist who has been published in Columbia Journalism Review, The Dallas Morning News, Racked, CityLab and The Development Set. Follow her @JulissaTrevino.

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