Dandruff is associated with an imbalance of the major bacterial and fungal populations of the scalp

In brief

Dandruff, a scalp disorder characterized by an abnormal flaking of the scalp, might be due to the increased proliferation of fungi such as Malassezia restricta: This article reports that dandruff is associated with changes in not only Malassezia spp. but also in the proportion between fungal and bacterial populations. These observations on a wide variety of scalp microbial contaminants should be useful for the development of new anti-dandruff strategies that can address the scalp microbiome.

Introduction

Dandruff is a scalp disorder occurring in up to 50% of the population and is characterized by an abnormal flaking of the scalp, related to mild inflammatory reaction. Dandruff results from disrupted cohesion between the corneocytes and cell hyperproliferation leading to stratum corneum alteration. Dandruff might be due to the presence of fungi:  Malassezia restricta, Malassezia globose or Filobasidium floriforme. No association has been made so far between dandruff, fungi and bacterial populations on the human scalp. In this article, Clavaud et al. reports that dandruff is significantly associated with a higher amount of both M. restricta and Staphylococcus epidermidis and a lower amount of Propionibacterium acnes compared to a control population.

Major Species Found on Scalps with or without Dandruff

Culture-independent methodologies, cloning and sequencing techniques performed on samples of 10 normal individuals and 9 dandruff individuals revealed that Propionibacterium and Staphylococcus were the two major bacterial species found in the scalp independently of the presence of dandruff. Malassezia restricta was the major fungal species present on the scalp with or without dandruff. Interestingly, dandruff was associated with changes in the proportion between fungal and bacterial populations. Dandruff was associated with an increase of ...