Q: My scalp often gets flaky. How do I know if I have dandruff or something else?
It’s hard to ignore. Your scalp itches, and flakes of skin linger in your hair or fall onto your shoulders, leaving white specks on your clothes. Is it dandruff?
Dandruff is “so common,” said Dr. Carolyn Goh, a clinical professor of dermatology at UCLA Health, who specializes in hair and scalp disorders. Research published this year estimated that about half of the world’s population is affected.
Experts are still working to understand what causes dandruff. What they do know is it’s a chronic but manageable issue that can come and go, Dr. Goh said.
Dandruff is a specific skin condition, but several other health problems can cause a flaky scalp. Here’s what to know.
What causes dandruff?
Dandruff is considered a mild type of seborrheic dermatitis, an inflammatory condition that causes a scaly rash on areas of the skin with lots of oil glands, like the scalp and face, said Dr. Adam Friedman, a professor and chair of dermatology at George Washington University.
Experts think there are various causes of seborrheic dermatitis, including the overgrowth of an oil-loving yeast called Malassezia, which naturally lives on the skin, as well as increased oil production and inflammation. While all of these elements contribute, Dr. Friedman said, “it’s unclear what happens first.”
All three components can alter the scalp’s microbiome, he said. They can weaken and damage the skin barrier and cause flaking, itching and greasy, scaling skin, said Dr. Oyetewa Asempa, a dermatologist in Dallas who specializes in hair and scalp disorders.
Dandruff is limited to the scalp, while other forms of seborrheic dermatitis can occur elsewhere on the body, Dr. Asempa said.
Anyone can get seborrheic dermatitis, but it’s most common in babies, where it’s called cradle cap, and in adolescents and older adults, according to the American Academy of Dermatology.
In most instances, dandruff can be treated — and prevented — with an over-the-counter dandruff shampoo containing selenium sulfide, pyrithione zinc or ketoconazole. These ingredients target the yeast, oil and skin cell buildup on the scalp, Dr. Friedman said.
Dr. Asempa said you may need to see a dermatologist when seborrheic dermatitis is severe. The doctor may prescribe a variety of treatments, including stronger dandruff shampoo, an antifungal cream or foam, or a topical corticosteroid to reduce inflammation, she said. Other options include antifungal pills and a medication that inhibits a specific enzyme that drives inflammation, Dr. Goh added.
What other conditions cause a flaky scalp?
Psoriasis — a chronic autoimmune condition in which skin cells turn over so quickly that they build up and form plaques — can look “very similar” to seborrheic dermatitis, Dr. Goh said. Psoriasis can occur anywhere on the body, including the scalp, and can cause flaking, burning, itching and hair loss, according to the A.A.D.
Doctors may recommend different treatments for psoriasis, depending on how severe it is, including topical steroids or systemic medications, which work throughout the body, said Dr. Starling Haynes, an assistant professor of dermatology at the Yale School of Medicine, who specializes in hair and scalp disorders.
Allergic contact dermatitis — in which your scalp has an allergic reaction to a hair care product or something else it comes in contact with — also causes a rash, scales and burning, Dr. Asempa said. She said the symptoms usually go away once you’re no longer exposed to the irritant.
Scaliness on the scalp can also be a sign of the fungal infection tinea capitis, commonly known as ringworm, Dr. Asempa said. It can itch and cause patchy hair loss, Dr. Goh added. Ringworm is contagious and common among children. The treatment is usually oral antifungal medications, Dr. Haynes said.
Some scalp conditions that cause permanent hair loss, known as scarring alopecia, create scaling around the hair follicles as well as flaking, redness and itching on the scalp, Dr. Friedman added.
How can I manage a flaky scalp?
Dr. Goh recommended starting with washing your hair more frequently than normal and “really getting the scalp clean.”
She explained that sometimes people attribute itchiness and flakes to dryness, so they’ll wash their hair and scalp less often, which increases oil buildup and worsens the problem.
You can also try an over-the-counter dandruff shampoo, Dr. Haynes said. Massage it into the scalp and leave it in for a few minutes before rinsing, Dr. Friedman said.
Avoid using hair products with fragrance or gritty scrubs that could damage the skin barrier and cause irritation, Dr. Haynes said.
If your scalp still itches and flakes after about a month of using a dandruff shampoo, Dr. Haynes said, consult a dermatologist. She said to see someone sooner if you also have hair loss, scalp pain or pustules on the scalp.
Checking with a dermatologist is the only way to know for sure what’s causing a flaky scalp and to receive the most effective treatment, Dr. Goh said.
She added that dandruff is a “chronic issue”: “Even if you have a good control of it at some point, you tend to have to continue managing it,” she said.
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