An ongoing bacterial battle in the scalp could hold the itchy truth about dandruff.
Fungi have been previously thought to be the primary driver of dandruff. New findings, however, pointed to the imbalance between two competing bacteria – namely Propionibacterium and Staphylococcus – that naturally colonize the human scalp as the factor determining if the host person will have the itchy condition.
“[O]verall fungi did not exhibit an important role in the severity of dandruff,” wrote the authors led by Zhijue Xu of Shanghai Jiao Tong University in China, referring to the Malassezia fungus that has long been implicated in the scalp problem.
Instead, they pointed to a stronger relationship between bacteria and dandruff, which has been prevalent for centuries and currently affects almost half of the global population. It is primarily characterized by dry skin flakes combined with sebum, an oily substance produced by skin glands in the scalp.
Dandruff naturally begins at puberty and peaks during teenage years until the early twenties, and declines from there, but lifestyle changes and medicinal shampoo formulations can only control it and cannot provide actual cure.
The team sought to better understand this mysterious disorder by studying 174 dandruff samples gathered from 59 Chinese individuals aged 18 to 60 years. With varying dandruff levels, the subjects were asked to wash their hair two days before testing.
The results: the two microorganisms, the dominant ones among hundreds found on the scalp, appeared to inhibit each other’s presence. Propionibacterium levels decreased while Staphylococcus increased in a bad case of dandruff.
The researchers recommended adjusting bacterial balance in the scalp such that Propionibacterium is enhanced and Staphylococcus – also linked to infections in the nose and other skin areas – is suppressed. Sebum and higher water levels in the scalp environment emerged as a food source for the former.
It is unknown whether staph bacteria leads to a dry scalp and dandruff, or if such conditions encourage bacterial growth in the first place. The answer, however, could produce better treatments than current remedies such as zinc-pyrithione shampoo, which boasts of antifungal properties as well as staph-killing effects.
The findings were published in the journal Scientific Reports.