How to Figure Out Whether You Have Dry Scalp, Dandruff, or Seborrheic Dermatitis

Yep, there's a difference.

Woman looking at her scalp by sectioning her long black hair
Photo: Getty Images

A dry and itchy scalp is irritating and can often cause discomfort. And if you just so happen to be sitting amongst friends while frantically scratching your scalp, things can get nerve-racking — especially if anyone catches a glimpse, or some flakes.

But you'll be pleased to know that concerns like dandruff, seborrheic dermatitis, and dry scalp are common problems, and there are a ton of people itching (excuse the pun) to find out the cause, as well as solutions.

"Anyone can get dry scalp or dandruff," says Sophia Emmanuel, certified trichologist and founder of Crown Worthy. "The key is to pay attention to what is causing the scalp condition. Often, these are not isolated scalp conditions. You can have a combination of both dandruff and dry scalp. Seeking professional advice from a dermatologist or a trichologist can help with diagnosing the problem."

Here, we talk with the expert to find out the differences between seborrheic dermatitis vs. dandruff, and dry scalp.

Seborrheic Dermatitis vs Dandruff, or Dry Scalp Which Is It?

Seborrheic dermatitis is considered a chronic form of eczema. It usually appears on the body where there are a lot of oil-producing (sebaceous) glands — like on the upper back, nose, and scalp. It can also appear around the folds of the nose and on the eyebrows, says Dr. Iris Rubin, Dermatologist and Founder of SEEN Hair Care.

An inflammatory reaction to excess malassezia, a fungus naturally found on the skin's surface, is usually the cause of seborrheic dermatitis. The malassezia overgrows and the immune system overreacts to it, leading to an inflammatory response that results in skin changes and scaly patches.

"Dandruff is a milder form of seborrheic dermatitis, and is restricted to the scalp," says Dr. Rubin. "Dandruff typically lacks visible inflammation." Chances are if you've ever scratched your scalp and noticed unpleasant white flakes on the collar of your shirt, you've probably experienced dandruff.

Dandruff is caused by malassezia found on the scalp, it feeds on the oils, breaking them down and leaving oleic acid in its place. Sensitivity to oleic acid is what can cause dandruff. If you are sensitive to oleic acid, your body will respond by attempting to shed the irritant by quickening skin cell renewal. The skin cells renew faster than usual, which causes dead skin cells to accumulate as flakes and shed more quickly, which results in dandruff. "The faster the scalp sheds, the worse dandruff becomes," says Emmanuel. "This is why some people shampoo their hair and in three days, they notice dandruff again."

A dry scalp presents similar symptoms to dandruff, including irritation, itching, flaking, and in some cases inflammation. However, Dr. Rubin explains that dry scalp is caused by dry skin, and sometimes irritants on the scalp.

Undeniably, a flaky scalp is aesthetically displeasing, but taking a closer look at the flakes can help reveal what's going on. "As dandruff is often caused by too much oil on the scalp, the flakes tend to be larger pieces of skin that are oily in nature," says Emmanuel. "When the scalp is dry, the flakes are usually fine, very dry, and much smaller in size." Dandruff flakes are usually white or yellowish, while flakes associated with dry scalp tend to be smaller and are typically white.

According to Dr. Rubin, seborrheic dermatitis usually presents itself as scaly yellow or red patches with associated itching. This condition can also lead to swelling and inflammation of the skin.

What Causes Dry Scalp?

A dry scalp is often combined with dry skin in other areas of the body. There are many reasons why the scalp may not produce or hold enough moisture, including:

Weather

Cold weather dries out the skin all over your body, including the scalp. And while we all tend to blast the heat when it's cold, this can have a drying effect on the skin.

Haircare

Processes such as blow-drying on a high heat, coloring, chemical straightening, or haircare products can cause the scalp to become dry. "Using a shampoo that has a very high pH level can cause the pH level of the scalp to become imbalanced," says Emmanuel.

Stress

Stress increases the production of certain hormones and releases pro-inflammatory chemicals that can compromise the scalp's barrier function. This means it's easier for moisture to escape, potentially leaving the hair and scalp drier.

Nutritional Deficiencies

Vitamins provide nutrients that help maintain a healthy scalp. Not getting enough of some of the key vitamins in your diet can cause dry scalp. "Vitamins B6, B12, and essential fatty acids, like omega-3s, are a lubricant for our body and can help to keep the scalp hydrated and healthy," explains Emmanuel.

Dehydration

Staying well hydrated can help prevent dry scalp. If you're dehydrated, your body will direct much-needed moisture to more critical functions, leaving your scalp and hair to fend for itself. Water is the main source of energy for hair cells, it hydrates the scalp, the hair strands, and generates new hair growth. Dehydrated skin lacks moisture from the inside and can cause flaking, itching, and irritation of the scalp.

VIDEO: What To Eat For Healthy Hair & Nails

What Causes Dandruff?

Pinpointing the exact cause of dandruff is a bit more complex than dry scalp. However, there are a few common culprits, these include:

Malassezia Globosa

This fungus is a major dandruff culprit. It is naturally found on everyone's scalp, and in 50% of people, it doesn't cause a problem. "While sebum [a natural, waxy oil produced by the scalp] is essential to keep the scalp's moisture balance normal, excess sebum triggers growth of malassezia globose," says Emmanuel. "When the fungus grows too rapidly the normal renewal of skin cells is altered and dead skin cells shed faster than normal, resulting in dandruff."

Infrequent Shampooing

Infrequent shampoo days can promote dandruff as excess dead skin cells are given the opportunity to accumulate and sit on the scalp. When dead skin cells overgrow, they become flaky and irritated, which leads to shedding and itching.

Diet

"Reduce bad fats, added sugar, processed food, and dairy products in your diet," says Emmanuel. These foods can promote excess oil production on the skin and scalp. Fungus' that cause dandruff, such as malassezia globosa and candida, feast on the saturated fatty acid produced, making dandruff worse.

Weather

Dandruff can occur at any time of the year and is not exclusive to cold, winter months. Humid, summer weather means excessive sweating, which creates the perfect environment for malassezia globosa to thrive and cause a dandruff flare-up. Emmanuel adds that cold weather can be a problem too, as the drying forces of cold winter air and overheated indoor spaces can upset moisture balances in the skin. "This fluctuation in temperatures dries out the scalp, leading to flaking," she explains.

Stress and Hormonal Fluctuations

Hormonal changes, like puberty and pregnancy, can cause dandruff in people who don't usually experience it. Stress can also cause hormonal fluctuations as cortisol levels (aka the stress hormone) tend to spike, which increases oil production on the scalp. "Stress hormones can disrupt the skin's barrier function, and trigger skin irritation and inflammation," says Emmanuel. "This is why you may find that your scalp gets itchy, flaky, and overly sensitive and greasy when you are going through a stressful period."

Candida Overgrowth

Candida albicans is a fungus that normally lives within the body in small amounts. "An infection called candidiasis can occur when there is an overgrowth of candida albicans, this can cause problems such as dandruff," says Emmanuel. "If you have a persistent case of dandruff that is not clearing up with normal treatments, a trichologist will usually check if candida overgrowth is the cause." Candida thrives in warm and moist areas but can also develop if the skin has become unbalanced due to medical conditions, stress, medication, harsh chemicals in haircare products, or an unhealthy diet. "A diet high in added sugar, dairy, fried foods, and processed foods will increase candida that lives on your skin," Emmanuel adds.

What Causes Seborrheic Dermatitis

An excess amount of oil in the skin and an inflammatory response to an overproduction of malassezia are considered to be the most common causes of seborrheic dermatitis.

Other factors thought to increase the risk of seborrheic dermatitis include:

Stress

Seborrheic dermatitis tends to be more common in people who are experiencing depression or emotional stress due to hormonal fluctuations.

Immunosuppression

A compromised immune system can increase the risk of developing seborrheic dermatitis. Individuals diagnosed with HIV/AIDS are at increased risk of developing the condition.

Increased Oil Production

Increased sebaceous activity in the skin is linked to seborrheic dermatitis. The sebaceous glands are at their peak activity right after birth and again throughout adolescence. Males are more likely to get seborrheic dermatitis because they tend to produce more sebum than females.

How to Treat Dandruff, Dry Scalp, and Seborrheic Dermatitis

"Many people experience scalp irregularities, understanding the causes and knowing about the solutions are the first steps towards improving and stabilizing the condition," Emmanuel explains.

Below, we share a few ways to combat dandruff, seborrheic dermatitis and dry scalp.

To Treat Dandruff

Itching and flaking caused by dandruff often respond well to over-the-counter shampoos and treatments. Emmanuel recommends using shampoos that are pH balanced like Giovanni 50-50 Balanced Hydrating Clarifying Shampoo. "The pH of the skin ranges from 4.2 to 6.5," she explains. "Use shampoos within this range so the pH of the scalp is balanced."

Using a scalp treatment before you shampoo can also help to control dandruff. "Scalp treatments help to lift dandruff and control bacteria overgrowth," she adds. Emmanuel also recommends using a detoxifying mask, like Philip Kingsley Flaky Scalp Mask. "These masks are designed to break down flakes and help keep dandruff more controlled."

And pay close attention to the foods you are eating as certain foods can make dandruff worse. "You can use an elimination strategy," Emmanuel suggests. "Start by removing added sugars, dairy, bad fats, and processed foods, to see if dandruff improves."

To Treat Seborrheic Dermatitis

"Oil on the scalp can create an ideal environment for malassezia to overgrow, so washing the hair more frequently, in some cases daily, can be helpful," says Dr. Rubin. "Avoid hair care products with heavy oils that can be food for the yeast. Periodically using a mediated shampoo that includes ketoconazole, selenium sulfide, salicylic acid or zinc pyrithione, can also be helpful for prevention."

To Treat Dry Scalp

Stay hydrated by drinking plenty of water, this helps to balance the moisture in the scalp. Eat more plant-based foods, and foods rich in antioxidants, including, strawberries, blueberries, artichoke, goji berries, spinach, raspberries, ginger, garlic, turmeric, dark chocolate, avocado, salmon, sardines, green tea. "These foods help to reduce inflammation, which will help combat itching," shares Emmanuel.

Also make sure to use shampoos with calming ingredients like lavender, chamomile, and peppermint to help soothe and calm irritation.

When it comes to which shampoo to use, Dr. Rubin sats dry scalp responds better to gentle, non-irritating shampoos, rather than medicated shampoos typically used for seborrheic dermatitis. "In a 30 patient dermatologist graded clinical study, 93% with dry scalp improved after using the SEEN Essential Bundle (shampoo and conditioner) for 4 weeks. SEEN uses a milder sulfate-free surfactant that won't overly strip the scalp of its natural oils. It's also clinically proven to be non-irritating and non-comedogenic so it won't clog the pores and is safe for sensitive skin," says Dr. Rubin.

Lastly, aim to restore moisture to the scalp by applying products like jojoba oil which has moisturizing and antibacterial properties, making it a great, natural choice for fighting dryness. Using soothing cream-based products on the scalp before you shampoo is also very beneficial, adds Emmanuel. "Creams work by leaving behind some moisture on your scalp so that tight, itchy feeling is soothed," she says.

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