Dandruff vs. Dry Scalp: How to Tell the Difference and Treat Both

When considering reasons for an itchy, flaky scalp, it's no surprise to expect that dandruff is the culprit due to its notoriety as a common scalp condition. However, a dry scalp can also cause these exact same symptoms, making it a challenge to distinguish between the two—particularly when seeking relief from scalp discomfort.

To help guide you in the right direction for scalp care and treatment options, we consulted dermatologists Blair Murphy-Rose, MD, and Robyn Gmyrek, MD, as well as certified trichologists William Gaunitz, WTS, and Gretchen Friese. Plus, these hair experts broke down what causes dandruff vs. dry scalp and when to seek professional help.

Keep reading to learn what sets dandruff and dry scalp apart and how to treat both.

What Is Dandruff?

Dandruff is a scalp condition that causes dry skin to flake off the scalp. Often considered a mild form of seborrheic dermatitis, this condition may cause scalp itchiness and redness as well. According to Dr. Murphy-Rose, dandruff is also a chronic condition that waxes and wanes over time.

“Dandruff is caused by an elevation of fungus on the surface of the scalp," says Gaunitz. "The main difference between dandruff and a dry scalp is that dandruff is an actual medical condition, whereas a dry scalp is simply a hydration issue,” he says.

What Is Dry Scalp?

While both dryness and dandruff can make your scalp itch and lead to flaking, a dry scalp isn't necessarily a chronic condition and can be improved by making simple adjustments to your hair care routine. “Dry scalp may improve with less frequent shampooing,” says Friese. She notes that it is possible to have both dry scalp and dandruff, which is why most people find it difficult to tell the difference between the two.

Dandruff Causes

Dandruff is often associated with "dirty scalps" and an overall idea of "poor personal hygiene," when in reality, it can happen to anyone. “The cause of dandruff is not entirely understood, but it is often associated with excess oil production and an overgrowth of fungus, particularly Malassezia sp, on the scalp,” Dr. Murphy-Rose says. “The scalp contains an abundance of hair follicles with sebaceous glands that produce large amounts of sebum—an oily substance—creating an ideal environment for fungi to thrive in.”

And when you pair that fungi with excess oil, microscopic dead skin cells that would normally slough off unnoticed stick together in clumps that present themselves as tiny-yet-noticeable white flakes. Scalp fungus is totally normal, and the immune system typically controls it, adds Gaunitz. “There are certain causes that lower the scalp immune state, like low vitamin D3 or ferritin, genetic history, an inflammatory diet, aggravating hair, and scalp products, or allergies,” he explains, noting that all of these factors can play into whether or not fungus will thrive on your scalp. 

While the main cause of dandruff is the aforementioned fungal growth, Dr. Gmyrek reports that stress can take a toll on your scalp health as well and thus can be another culprit in the war against white flakes. “This ‘stress’ can be psychological—such as relationship trouble—work deadlines, etc… or it can be physical stress on your body, such as having a cold, fighting an illness, having surgery, or simply being run down,” she says.

Dandruff Symptoms

The most common sign of dandruff is when you start to notice white flakes falling from your scalp to your shoulders and back as you brush or tousle your hair. Of course, before such flakes appear, all of our experts say that itchiness and redness will likely present themselves first. 

Dry Scalp Causes

According to Friese, a dry scalp occurs the same way that dry skin does: When it doesn’t produce or retain enough moisture. “Like other forms of dry skin, this can cause itching, flaking, and irritation,” she says. It’s important to understand that you can wash your scalp’s hydration down the drain if you shampoo it too regularly. What’s more, what you wash it with can also lead to drying—that’s why it’s so important to use well-formulated haircare products designed to hydrate your strands without weighing them down or stripping them. 

Products and showering aside, Dr. Murphy-Rose says that climate (think seasonal and year-round; high levels of heat or cold and low levels of humidity), excessive sun exposure, and genetics can also lead to a dry scalp.

Dry Scalp Symptoms

Aside from an itchy scalp and dry hair, according to Friese, with a dry scalp, you may see fine flakes as a result of extreme dryness, just as they can appear on your face during the harshest, coldest seasons of the year.

Dandruff vs. Dry Scalp Appearance

One of the easiest ways to tell the difference between dandruff and flaky, dry scalp is the appearance of the flakes. Flakes from dandruff tend to be much larger and incredibly visible—think flaky, Maldon sea salt. Flaky dry scalp tends to be much finer and smaller.

Prevention and Treatment

There are a multitude of things you can do to treat dandruff and a dry scalp, including:

Dandruff

• Use a medicated shampoo: Dr. Gmyrek says to reach for a shampoo formulated specifically for dandruff or seborrheic dermatitis at least two times a week. “These shampoos contain salicylic acid, ketoconazole, zinc pyrithione, or selenium sulfide, and will work to decrease oil and fungus, and flakes as a result,” she says.
• Up your omega-3 Intake: According to Gaunitz and research studies, omega-3s help regulate oil production, which can reduce the amount of fungal growth and flaking. 
• Take vitamin D supplements: Speaking of supplements, Gaunitz adds that one of the best ways to prevent dandruff is to take vitamin D3 supplements. This makes sense, considering, according to the American Academy of Dermatology, vitamin D helps slow the rate of rapid skin cell growth—which can be a factor in more extreme cases of dandruff and psoriasis.
• Stock your hair care routine with tea tree oil: Tea tree oil is anti-inflammatory and anti-microbial, making it a great option for scalp rebalancing. Thankfully, these days, it's mixed into a slew of hair treatments, shampoos, conditioners, and masks.
• Try meditation (and/or exercise): Seriously though. High levels of stress can trigger dandruff and excessive flaking. As if you need another excuse to zen out, let this be it. Just remember: The calmer you are, the less likely a dandruff flair will be.

Dry Scalp

• Try a pre-shampoo scalp treatment: When your scalp is dry, it needs all the help it can get to feel comfortable again. One of the best ways to do this is to start your hair care routine with a product designed specifically for your scalp’s comfort and well-being.
• Use a moisturizing, gentle shampoo and conditioner: Since a dry scalp can be in part due to irritation, swapping out any harsh shampoos and conditioners for ultra-gentle ones can seriously pay off. When looking for gentle shampoos, you’ll want to steer clear of fragrance and essential oils and veer toward hydrating, soothing ingredients like aloe vera and oat milk.
• Eliminate products with alcohol as the main ingredient: Many hair care products are made with alcohol. It’s when alcohol is the main ingredient that it’s particularly worrisome. For this reason, when scouring for the best hair care products for your mane goals, make sure none of the ones you make room for in your routine have alcohol in the first five to 10 ingredients. Your scalp (and ends, honestly) will thank you.
• Wash less often: Remember, you can wash your scalp’s natural oils away if you shampoo too frequently. That said, try to wash no more than every other day when attempting to cater to your scalp—and always use lukewarm (not scalding hot) water when doing so. While the temperature may not seem like a big deal, when it comes to the hydration of your scalp and skin, the hotter the water, the more dried out they'll both become. Yikes.
• Add a humidifier to your home: Part of having a dry scalp comes down to the climate you live in. If you live somewhere super dry—or if it’s summer or winter (aka the driest times of the year—it helps to have a humidifier to pump a little moisture back into your environment. While there are plenty of humidifiers to choose from, the Dyson Pure Humidify+Cool is the first machine to date to be recognized by the National Psoriasis Foundation (NPF) as a solution for people with psoriasis, psoriatic arthritis, and/or individuals living with severely sensitive skin. Since psoriasis involves flaking skin—and since dry skin is associated with sensitivity—this machine is a shoo-in for anyone looking to pamper their scalp. 
• Try Probiotics: You can help balance the flora of your skin or your scalp with probiotics, and many body care products now contain them. Balancing the flora of your scalp can lead to it retaining moisture more efficiently. There are hair products made that contain probiotics, and you also may benefit from taking them internally. Taking a complex that contains additional ingredients useful for hair, skin, and nails can provide beneficial nutrients for your scalp.

When to See a Doctor

When dandruff progresses from a mild to extreme form, Dr. Gmyrek says that it can cause skin cells to multiply more quickly than usual, which results in heavier flakes, persistent itching, noticeably more inflammation, and, in some cases, redness. When this happens, what started as a mild form of seborrheic dermatitis can excel into a more serious form. But don’t worry: According to Dr. Gmyrek, the inflammatory condition is incredibly common and not super difficult to treat. However, if it's been a month and you feel like you’ve tried everything and your symptoms aren’t getting any better, it’s best to visit your dermatologist for directions on how to proceed.

The Final Takeaway

Dandruff and a dry scalp are often mistaken for one another, as they both share the same symptoms of itchiness, white flakes, and redness. However, they differ, as dandruff is caused by fungal growth or stress, while dry scalp is caused by a lack of moisture in the skin. The best way to care for either condition should it arise is to remember to treat your scalp like the rest of your body's skin: With daily attention and targeted care. If you've tried the suggested at-home treatment and are not seeing improvement in your symptoms, consult a trusted dermatologist.