Ask a Beauty Editor: What's the Difference Between Dandruff and Dry Scalp?
Ever wanted to pick the brain of a beauty editor? Or get beauty product recommendations from someone who has tried them all? You've come to the right place. In our weekly series, beauty editor Hana Hong answers your biggest skincare, hair care, and makeup questions, all submitted by Real Simple readers. Tune in every Tuesday and submit your own burning beauty questions here for a chance to be featured.
Reader question: Help for dry winter scalp! Dandruff shampoos only make it worse. —@brandyo
Here's the problem: It sounds like you're trying to treat a dry scalp with dandruff shampoo, which is a common mistake. People often use dry scalp and dandruff interchangeably because they have the same symptoms, however, they are two different conditions that have different treatment plans.
To get to the root (ha) of the issue, it's important to know the difference between dry scalp and dandruff—and how to identify the two so you can properly diagnose (and treat!) your condition.
What Is Dry Scalp?
While a "dry scalp" isn't a medical diagnosis (it's more of a description), it's a common condition triggered by everything from excessive washing to harsh hair care products. In some cases, it could also signify an underlying medical condition, such as psoriasis, contact dermatitis, eczema, or sunburn.
The irritation will produce the same symptoms as your classic dandruff (i.e., itching and flaking), but it's important to note that a dry scalp is caused by the scalp's inability to produce enough sebum and natural oils. "When the scalp lacks moisture, it becomes excessively dry and leads to shedding of dead skin," says Hadley King, MD, board-certified dermatologist in New York City.
What Is Dandruff?
On the other hand, seborrheic dermatitis (aka dandruff) is an inflammatory condition of the scalp associated with an overgrowth of harmless yeast. While dry scalp is caused by a lack of moisture, dandruff is triggered by excess oil production.
"Seborrheic dermatitis is characterized by flaking and redness, what we typically call dandruff," says Dr. King. "A yeast found on the skin called Malassezia can contribute to the inflammatory response in seborrhea. This yeast feeds on sebum and therefore thrives in oily areas." (Note: This is why most anti-dandruff shampoos have antifungal properties.)
"We do not know exactly what causes seborrhea, but it does seem to be multifactorial," Dr. King adds. "These factors may include genetics, stress, diet, and certain medications such as interferon and lithium."
How to Identify Dry Scalp vs. Dandruff
Although dandruff and dry scalp have very similar symptoms, experts say there are a couple clues that differentiate them. With a dry scalp, the flakes are usually white specks, while dandruff is tinted yellow.
"Dandruff also has an abnormally accelerated renewal of scalp skin cells that fall off as scales and clusters," says Antonella Tosti, MD, board-certified dermatologist and medical advisor for Keeps. In other words, the excess oil causes microscopic dead skin cells to stick together in clumps. On the other hand, flakes produced by a dry scalp are smaller and fall down like tiny dust particles.
How to Treat Dry Scalp
If you've gotten this far and think you may have a dry scalp, keep reading (otherwise, skip to the next section). When it comes to dryness, gentle products and soothing ingredients are key, which is why a medicated dandruff shampoo (the opposite of soothing and gentle) will only make it worse.
What's more, the frequency of washing can also aggravate the issue—that's why it's so important to wash sparingly and only with hydrating hair care products. Stay away from shampoos with detergents, especially the two most common ones: ammonium lauryl sulfate and ammonium laureth sulfate. Instead, opt for formulas infused with hydrating ingredients like hyaluronic acid.
In addition to shampoo, a weekly scalp mask and/or conditioning treatment can also help. Jana Rago, a hairstylist and owner of Boston-based Jana Rago Studios, adds that hot oil hair treatments have many benefits for a dry scalp, noting they can "help stimulate blood circulation and release flaky, dry skin sitting on top of the scalp, leaving your scalp moisturized and refreshed once it's washed out."
If you use a lot of hairstyling products, it might be worth ruling them out for contact dermatitis. Some chemicals found in styling gels, sprays, and creams can be irritating, so try patch-testing them on your skin before applying them all over your scalp.
The climate is another major culprit behind dryness, so pay attention to excessive sun exposure. This can lead to a dry scalp, and even worse, sunburn, which will further cause your scalp to flake as it heals. To counteract this, apply sunscreen to your scalp—my fave is Supergoop Poof 100% Mineral Part Powder SPF 35 ($34; sephora.com), which comes in a powder for easy application.
If your condition is still not improving after a few weeks, Dr. King recommends seeing a dermatologist, who may examine your scalp for chronic skin conditions and prescribe a topical corticosteroid.
How to Treat Dandruff
The goal with seborrheic dermatitis is targeting the yeast and therefore decreasing the inflammatory response. According to Dr. King, you should look for ingredients that are antifungal and antimicrobial, including selenium sulfide, pyrithione zinc, ketoconazole, coal tar, and tea tree oil. She adds that salicylic acid may also be useful when used in conjunction with other treatments since it helps to reduce scaling on the scalp.
The good news is that these ingredients are all commonly found in a slew of OTC hair treatments, shampoos, conditioners, and masks. Dr King recommends Dove Dermacare Scalp Dryness and Itch Relief Anti-Dandruff Shampoo with Pyrithione Zinc ($5; walmart.com), a mild, pH-balanced formulation that can decrease yeast on the skin without causing irritation. For more severe cases, I personally swear by Nizoral A-D ($11; amazon.com), a formula powered by ketoconazole to wipe out lingering fungi in just one application.
If you're still not seeing improvement after a few weeks, consult a dermatologist who can prescribe a stronger topical and/or oral medication.