If you’ve ever experienced a flaky scalp then you know how uncomfortable it can be. Between the itch, redness, and overall irritation, the flakes can be even more unsettling when in the presence of friends. Chances are you have one of two situations: dandruff or a dry scalp. “Dandruff and dry scalp can be a sign of the condition called seborrheic dermatitis,” says board-certified dermatologist Dr. Anthony Rossi. “Both conditions can affect the sebaceous gland-rich regions of the scalp, face, and trunk.”
Although dandruff and dry scalp can both present with itchy, flaky skin on the head, they are not the same condition. “Dandruff is caused by oil and buildup from skin, products, or in some cases bacteria or fungi,” Mercedes Doan, medical aesthetician and manager of aesthetic services & education at Ever/Body, tells TZR. “On the other hand, dry scalp is caused by dehydration and loss of moisture or natural oils.”
And as unbearable as the two might be, neither is an unusual condition. “Dandruff is a common scalp disorder affecting almost half of the population and can be found in any gender or ethnicity,” says Dr. Orit Markowitz, New York City Board-Certified Dermatologist and Founder of OptiSkin. The key is to pay attention to what is causing the scalp condition and to focus on your overall scalp care.
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Dandruff Vs Dry Scalp
Medically known as pityriasis capitis, dandruff involves “skin cells of the scalp that shed at a faster rate than normal, creating a buildup,” says Bridgette Hill, founder of Root Cause Scalp Analysis, certified trichologist, and hair science expert. “In a normal healthy scalp, the horny layer, or stratum corneum, has 25-35 tightly coherent cells. But when someone has pityriasis capitis, there are fewer than 10 layers that are not coherently formed, with deep crevices that result in development of what we call flakes.”
The two most common types of scalp dandruff are pityriasis capitis (dry dandruff) and pityriasis steatoides (greasy dandruff). Dry dandruff produces white, yellowish, or grey flakes that accumulate on the scalp. “With greasy or wet dandruff, the rapidly shedding skin cells bind together with scalp oil and produce mounds of dandruff that bind together. The color is often beige to yellow,” Hill tells TZR.
Meanwhile, a dry scalp is one that lacks moisture and has very little oil on it. While both dryness and dandruff can cause irritation and itch, the main difference is that dandruff is an actual medical condition caused by an elevation of fungus on the surface of your scalp, whereas a dry scalp is simply a hydration issue. Dandruff flakes tend to be more oily and large in size, while dry flakes are usually thin and much smaller.
What Causes Dandruff?
Dandruff is the result of an overproduction of yeast with a fungus called malassezia. “The overproduction of yeast interacts with the natural balance of malassezia on the scalp creating abnormal fungal growth,” says Hill. The scalp contains a plethora of hair follicles with sebaceous glands that produce an oily environment ideal for fungi to thrive in. When you pair the fungi with excess oil and yeast, the dead skill cells that would normally slough off unnoticed, end up sticking together in clumps as tiny yet noticeable white flakes.
Dandruff can also result from a buildup of products on the scalp. “When the scalp is overly sensitive from being exposed to certain chemicals present in hair care products or dyes, or just simply from the scalp either being too oily that it clogs the pores,” says Dr. Dendy Engelman, MD, FACMS, FAAD, board certified cosmetic dermatologist. Excessive shampooing can also cause dandruff by “removing the natural oil of the scalp, making it dry, irritated, and easily flaky,” says Dr. Hope Mitchell, MD, FAAD, board-certified dermatologist and founder of Mitchell Dermatology. Dr. Mitchell recommends Briogeo Organic + Australian 100% Tea Tree Oil as tea tree oil has anti-microbial and anti-inflammatory properties that will restore the natural oil content of the skin and reduce flakes.
Other causes of dandruff include: irregular shampooing, diet (processed food, added sugar, and dairy products can promote excess oil production for the fungi to feed on), weather (excess sweating in the summer and winter dryness), and stress and hormonal fluctuations (cortisol levels spike when under stress, increasing oil production on the scalp).
What Causes Dry Scalp?
“Dry scalp means there is a depletion in its moisturizing agent — sebum,” Hill tells TZR. Insufficient sebum production can be caused by: genetics, lifestyle, diet, hair styling habits, weather, environment, health, stress, hormones, and medications. Symptoms of dry scalp may include tightness, soreness like flakiness, and dry brittle hair.
Two of the biggest factors that lead to dry scalp are stress and dehydration. Stress can increase the production of certain hormones and release pro-inflammatory chemicals that can compromise the scalp’s barrier function — making it easier for moisture to escape the scalp. When your body is dehydrated, it will take moisture from other sources to deposit it into more critical functions — leaving your scalp and hair by the wayside.
Is It Possible To Have Both Dandruff & A Dry Scalp?
Unfortunately, yes. “It is common for scalp conditions to manifest symptoms limited to a particular part of the scalp and not show signs anywhere else on the scalp,” says Hill. For example, if your dandruff is caused by an overgrowth of yeast, you’ll likely also have a dry scalp since the malassezia feeds on the oil of the scalp — drying out the scalp even more.
How To Prevent & Treat Dandruff
The more oil on your scalp, the more fungi that will form. The more fungi that forms, the more it will stay trapped on your scalp in the oil — leading to further flaking, itching, and redness. The good news? The inflammatory condition is incredibly common and not super difficult to treat.
According to the experts, more shampooing may be required to manage dandruff. Hill suggests looking for products with selenium sulfide, salicylic acid, sulfur, coal, tar, zinc, and alpha hydroxy acids. “In general, zinc and coal tar-based products applied to the scalp (scalp masks, scalp tonics) with anti-microbial properties will prevent unhealthy bacteria and fungus that can be developed on the scalp because of dry flakes on the scalp,” she says. Gretchen Friese, BosleyMD certified trichologist, recommends the antibacterial and antifungal BosleyMD Anti-Dandruff Shampoo and a tar-based shampoo like Neutrogena T/Gel. “Coal tar slows how quickly skin cells on your scalp die and flake off,” she says.
Dr. Engelman also recommends Prose Root Source, which is designed to soothe and rebalance the microbiome of the scalp and encourage a healthy environment for hair growth.
Dr. Markowiz suggests Head & Shoulders as it’s formulated with selenium sulfide and zinc pyrithione. “Selenium sulfide is an anti-infective agent that relieves the scalp of itching, flaking, and redness,” the expert says. “While zinc pyrithione is an antifungal that targets the fungus and inflammation. It also regulates oil production.” As a tip, Hill encourages her clients to shampoo as often as needed but to alternate between dandruff fighting active ingredients and a gentle daily shampoo to maintain the balance of the scalp’s microbiome.
Using a scalp mask before shampooing can help lift the dandruff and control bacteria overgrowth. Other ways to combat dandruff include increasing your omega 3 intake (omega-3s help regulate oil production, reducing the fungal growth and flaking), take vitamin D supplements (slows the rate of rapid skin cell growth), and exercise (to manage the side effects of stress).
Of course, if you're experiencing scabbing, increased itching, redness, or prolonged outbreaks, it's best to visit a doctor.
How To Prevent & Treat Dry Scalp
How dry scalp is managed and controlled depends on the symptoms experienced. Hill encourages products with peppermint, eucalyptus, tea tree, rosemary, and aloe if the scalp is tight and mildly flaky. “Incorporating pre-shampoo treatments into your cleansing routine helps keep the dryness at bay and slows down the cellular turnover that causes dandruff,” she says. “Dry scalps need the sebum to not be removed from the scalp, so think of balancing shampoos that are not harsh, sulfate-free and retain the balance of the microbiome.”
Dr. Engelman recommends Detox Kit by Curlsmith. “It is a three-step system that consists of: a prebiotic primer which coats the hair with a protective shield, a probiotic detox which uses micro-fine exfoliating particles to deeply cleanse the scalp of dirt and buildup, and a calming post-biotic conditioner which soothes irritation.”
Blow drying hair, coloring, and chemically straightening hair can also cause the scalp to become dry. To combat this, look for a shampoo that has a lower pH level (under 4) to keep the pH level of the scalp balanced. Friese recommends BosleyMD Rejuvenating Scalp Scrub, which has naturally dissolving sugar particles to gently exfoliate the scalp and Lanza Scalp Remedy shampoo and conditioners to balance out the scalp pH of the scalp and soothe irritation.
Lastly, aim to restore moisture to the scalp by using lukewarm water when washing your hair (the hotter the water, the more dry your scalp will be), eliminate products with alcohol, and invest in a humidifier (dry scalp can also come from the climate you live in). Just remember that neither condition will disappear overnight, so be sure to stick with your treatment plan in order to maintain long-term scalp health.