Dandruff Is a Low-Grade Inflammatory Condition Featuring Hyperproliferative Keratinocytes, Interleukin-17-Producing T Cells, and N-Acyl Ethanolamines

This study reveals that dandruff is not just a flaking disorder but involves a low-grade inflammatory condition characterized by increased keratinocyte proliferation and differentiation. The research, which included full-thickness scalp biopsies from healthy volunteers and those with dandruff, found increased proportions of interleukin-17-producing T-cells and elevated CCL17 levels, suggesting a mixed Type-2/Type-17 inflammatory response. Despite these changes, there were minimal alterations in major skin immune cell populations and barrier lipid levels. Additionally, increased levels of N-acyl ethanolamines, such as anandamide, were observed, potentially suppressing inflammation to sub-clinical levels. These findings suggest alternative approaches for dandruff treatment by targeting its inflammatory components.