Dandruff is associated with the conjoined interactions between host and microorganisms

Abstract

Dandruff is an unpleasant scalp disorder common to human populations. In this study, we systematically investigated the intra- and inter-associations among dandruff, physiological conditions such as sebum of the scalp, host demographics such as gender, age and the region of the scalp, and the microorganisms on the scalp. We found that the physiological conditions were highly relevant to the host age and varied in different regions of the same scalp. The sebum quantity and water content were negatively correlated with the formation of dandruff and had significant relationships with the two dominant but reciprocally inhibited bacteria on the scalp (Propionibacterium and Staphylococcus). The dominant fungus (Malassezia species) displayed contrary roles in its contribution to the healthy scalp micro-environment. Bacteria and fungi didn’t show a close association with each other, but the intramembers were tightly linked. Bacteria had a stronger relationship with the severity of dandruff than fungi. Our results indicated that the severity of dandruff was closely associated with the interactions between the host and microorganisms. This study suggests that adjusting the balance of the bacteria on the scalp, particularly by enhancing Propionibacterium and suppressing Staphylococcus, might be a potential solution to lessen dandruff.

Sensitive scalp is associated with excessive sebum and perturbed microbiome

“…In our study, we found the most abundant bacteria on the scalp are Propionibacterium and Staphylococcus , concurrent with previous findings . Studies also suggested a reciprocal inhibition between the two main components . The bacterium P. acnes could hydrolyze triglycerides to release free fatty acids and promote bacterial adherence and produce bacteriocins to kill other strain, which might explain our results that the percentage of Propionibacterium was significantly increased in sensitive scalp, with less percentage of other strains and lower diversity.…”

“…In our study, no significant differences were noted on the average dandruff scores between NS and SS, indicating sensitive scalp might have different mechanisms with dandruff. Studies have been suggested the distinction between crown and occiput in biophysical parameters and sensations . Therefore, we performed all the measurements at two sites, crown and occiput.…”

Dysbiotic Bacterial and Fungal Communities Not Restricted to Clinically Affected Skin Sites in Dandruff

“…(Clavaud et al, 2013; Wang et al, 2015). More recently, Xu et al (2016) showed that host factors such as skin sebum and water content are related to dandruff. Analyzing scalp microbiome by NGS, the authors found that dandruff is more closely related to bacteria than to fungi, and reported no significant association with Malassezia at species level, although some OTUs showed positive or negative correlation with dandruff (Xu et al, 2016).…”

“…More recently, Xu et al (2016) showed that host factors such as skin sebum and water content are related to dandruff. Analyzing scalp microbiome by NGS, the authors found that dandruff is more closely related to bacteria than to fungi, and reported no significant association with Malassezia at species level, although some OTUs showed positive or negative correlation with dandruff (Xu et al, 2016). Our results corroborate the relationship between dandruff and bacteria but not with Malassezia at species level, and showed for the first time increased diversity and dissimilarity among dandruff samples, affecting also asymptomatic skin sites.…”

The role of the microbiome in scalp hair follicle biology and disease

“…Corynebacterium spp., Streptococcus spp., Acinetobacter spp., and Prevotella spp. are listed among other significantly less numerous species . Some discrepancies between studies have also been presented; for example, Perez‐Perez et al .…”