Health Science Reviews

By Moleboheng Moipatli

We are all aware that a plethora of microorganisms reside in our stomachs. That is what is referred to as the gut microbiome. Well, if you are like me and you’ve never thought to question the origin of some of the skin-related disorders or diseases, then you are in for quite a surprise!

Have you ever wondered what causes the buildup of dandruff, an itchy and inflamed scalp? Well, it turns out we have bacteria and fungi naturally living on our scalps too! According to previous research, the human scalp accommodates diverse bacteria and fungi that influence both healthy and diseased scalps. Fungi have been reported to cause dandruff by activating specific proteins that break down oil produced by the scalp, and certain bacteria play a role in consuming the oil (fatty acids) to avoid accumulation that can eventually lead to irritation and inflammation, which are symptoms of seborrhoeic dermatitis.

Although the regular microbial communities there are complicated, little was known about the bacteria that reside on the human scalp. So, the researchers from Soochow University and other universities in China set out to test a theory that stated that skin problems might be caused by the collapse of a healthy microbiome, for example a drop in the variety of microbes and too much growth of some microbes. In the quest to test the hypothesis/claim, the researchers asked themselves two questions: i) Is there any difference between people with diseased scalps and normal scalps when looking at the structure and diversity of their microbial community? And ii) Is the bacterial and fungal harmony (network) disrupted?

To help answer these questions, the researchers combined different scientific methods that included taking samples from volunteers who were categorized into two groups: those with normal scalps and those with diseased scalps (subclassed to dandruff and seborrheic dermatitis). The samples were studied using a sophisticated DNA sequencing technique known as Illumina MiSeq Sequencing and other bioinformatics tools to investigate the bacterial and fungal microbial communities on scalps associated with D/SD and the relationship and differences between the scalp microbiomes in normal and diseased groups.

Their results showed that an increase in the diseased group (with dandruff and seborrhoeic dermatitis), the abundance of Staphylococcus was high as compared to the abundance/presence of other bacteria, such as Propionibacterium. They also showed that a type of fungi called Malassezia restrica was more abundant as compared to a different type of the Malassezia species, suggesting that these differences in the relative abundance of the microbial population may contribute to disease symptoms.