Management of Scalp Biofilm in Local Dermatosis: From In Vivo Visualization to Optimal Treatments

The fungi and bacteria on the human scalp play important roles in both health and disease. Scalp biofilms have pathogenic effects on cutaneous tissues, such as seborrheic dermatitis. However, investigations into scalp biofilms and their physiological effects on scalp skin are limited. In this study, we suggest an evaluation method through which the scalp is stained a reddish color using erythrosine to visualize scalp biofilms, which strongly depends on the presence of bacteria and fungi. We found that the physiological properties of the scalp significantly differed between high and low levels of stained red areas (sRAs) on the scalp. The sRA levels showed a strong positive correlation with IL-8 levels and sebum production. It is worth noting that the production of sebum has a dominant effect on the scalp microbiome via the growth of microbes, leading to the formation of a biofilm, as evidenced by changes in the sRA levels. Furthermore, the sRA levels could be reduced through the use of antimicrobial agents, such as climbazole and hexamidine diisethionate (HD), as well as the manipulation of the physical properties of the scrubs used in scalp care products. These scalp care products could potentially disrupt the formation and accumulation of a biofilm on the scalp, providing strong evidence for the importance of considering the scalp microbiome and its interactions with sebum in the development of biofilms. Consequently, we suggested that the administration of anti-microbial agents, such as climbazole and HD, could be an effective strategy to alleviate biofilm accumulation for the maintenance of scalp health.