Epidermal changes associated with symptomatic resolution of dandruff: biomarkers of scalp health

Background  Dandruff is a common scalp condition characterized by flakes, pruritus and sometimes mild erythema. These symptoms reflect underlying histopathologic and biochemical events that must be reversed if treatment is to be effective. Objectives  This study aimed to better characterize the state of the epidermis in dandruff and to determine how a defined set of skin surface biomarkers of this state change during a successful course of treatment with a potentiated zinc pyrithione (ZPT) shampoo. Methods  A population of dandruff sufferers was treated for 3 weeks with a commercial ZPT shampoo or a non-medicated product, and the effect of treatment on adherent scalp flake (ASF) scores was evaluated. Biopsies were taken from lesional sites at baseline and at the end of the study for histomorphometric and histopathologic analysis. Stratum corneum (SC) samples were likewise obtained for evaluation of biochemical markers of inflammation (IL-1α, IL-1RA, IL-8) and barrier integrity (keratin 1, 10, 11; involucrin; SC lipids; human serum albumin). The biomarker profile was evaluated first by comparison with that in non-dandruff subjects at baseline, and then to determine whether any treatment-induced changes were correlated with reductions in flaking in dandruff sufferers. Results  Taken together, our studies showed that treatment with the ZPT shampoo led to an improvement in the overall scalp condition as assessed by the resolution of flaking, reduction in epidermal thickness and inflammatory biomarkers, and a dramatic improvement in biomarkers of epidermal barrier integrity. Conclusions  The combination of biomarkers examined appears to be a good overall descriptor of the health of the scalp in dandruff, and changes in these biomarkers track with tissue-level events that underlie clinical efficacy in the treatment of dandruff by ZPT shampoo. For the first time, we demonstrate a set of tools that extend beyond flaking scores to provide insight into specific biological changes occurring on the scalp to enable an objective assessment of scalp health.