Scalp experts share tips, causes

Washing hair is sometimes not enough to combat dandruff.

Scalp and skin experts say there are various causes for the flaky skin condition — and not everyone can get rid of it by using standard shampoo.

Alexia Donovan, director of client services at the Barber Surgeons Guild, a hair restoration and grooming lounge with locations in New York City and Los Angeles, told Fox News Digital that she’s been helping patients and clients address dandruff and scalp health for 14 years.

“Several factors can contribute to dandruff — dry skin, psoriasis, oily scalp and fungus are the more common causes,” said Donovan, who is based in West Palm Beach, Florida.

What is dandruff?

Dandruff, also known as Pityriasis Capitis, is a non-inflammatory skin condition that results in scalp scaling, according to the National Institutes of Health.

“While winter months can cause dry scalp, the phrase ‘summer dandruff’ exists as sweat, dirt, humidity, pool chemicals and sun exposure can also trigger flakes,” she continued.

To address persistent dandruff, Donovan recommends using shampoos that contain zinc, selenium sulfide or ketoconazole, all ingredients that are added to most commercial anti-dandruff shampoos.

“If the dandruff is chronic and not improving, seek out a hair doctor or dermatologist to help as a prescription may be necessary,” Donovan said.

For those who have light dandruff that doesn’t require medical intervention, Donovan recommends washing hair with “a high-quality, mild shampoo” when it comes time to remove heavy styling products.

She also suggests daily hair and scalp brushing, so oil and dead skin buildup can be minimized in between washes.

Those who have their scalps exposed to the sun should consider wearing a hat to prevent sunburn on the scalp, according to Donovan.

The flaking that occurs with scalp burn often looks similar to dandruff.

Dandruff can be addressed when the scalp is regularly cleaned and hydrated, said Dr. Mariano Busso, a board-certified dermatologist who practices in Miami, Florida, and Beverly Hills, California.

For flaky scalps, he recommends that dandruff patients use “gentle shampoos” that are specifically made for dandruff removal.

These specialized shampoos are typically made with antifungal ingredients, which include zinc pyrithione, ketoconazole and selenium sulfide.

“Adding an antifungal shampoo to your routine will help you fight dandruff brought on by yeast overgrowth,” Busso told Fox News Digital.

He also noted that it’s important to fully rinse the scalp and hair to make sure there isn’t any leftover residue when washing.

Dandruff patients should also be careful when they’re styling their hair post-wash, Busso warned.

“The use of heat tools and styling products should be kept to a minimum because they might exacerbate dandruff,” he warned.

Research has shown that dandruff affects about 50% of the human population at some point in their lives, said Celestine Gitau, a trichologist — also known as a hair and scalp specialist.

She writes for international hair care trade groups, including The International Hair Authority, The Institute of Trichologists and Union of Barbers. 

“It presents with flakes on the scalp. The flakes are white or yellow in color,” Gitau, who’s currently based in Nairobi, Kenya, said via email.

Dandruff is typically caused by skin colonization of a yeast fungus known as Malassezia globosa, she said.

“Malassezia globosa feeds on sebum breaking it down to an oleic acid product,” she explained.  “The scalp becomes itchy and irritated by the presence of oleic acid in some people.”

She also said, “The irritation causes the skin cells to shed more quickly than usual in an attempt to get rid of the irritant.”

Dandruff-causing yeast tends to thrive in hot and humid environments, which could exacerbate the conditions, according to Gitau.

“Sweat does not evaporate as rapidly when the humidity is high,” she said. “This encourages the growth of Malassezia globosa increasing the chances of dandruff flareup.”

In terms of medicated shampoos, Gitau recommends formulas that contain yeast-fighting ingredients, such as ketoconazole, zinc, tar or salicylic acid.

The American Academy of Dermatology (AAD), a peer-reviewed journal and association based in Des Plaines, Illinois, notes that many people believe dandruff is caused by poor hygiene.

Yet research has shown that’s not always the case.

“Although infrequent shampooing can make dandruff more obvious, researchers are still studying the causes, which appear to be complex,” the AAD wrote in an online dandruff treatment guide.

People should follow the instructions printed on anti-dandruff shampoos, including the application duration, said the dermatology journal.

Some shampoos require users to leave the product on for about five minutes before rinsing while others do not, according to the AAD.

The AAD also notes that hair type and texture should be factored when treating dandruff. 

People with straight hair may need to use dandruff shampoos twice a week, while people with curly and kinky hair may need to use dandruff shampoos at least once a week.

“For most people, dandruff does not require medical attention,” the AAD wrote. “However, sometimes the flaking and itching that appears like dandruff is actually a medical condition, such as seborrheic dermatitis, psoriasis, fungal infections of the scalp, or eczema.”