INTRODUCTION

SeborrheicDermatitis (SD)is a chronic and relapsing inflammatory skin condition of sebum-rich areas such as the scalp.It is characterized by erythema, mild to moderate scaling resulting in greasy and flaky scalp, and is sometimes associated with pruritus.¹ When only mild scaling without visible inflammation is observed, SD is called dandruff (D). Various environmental, intrinsic and host immune factors may contribute to the development of SD, leading to an alteration of the sebaceous gland activity and sebum composition, epidermal barrier function, and skin surface fungal colonization, which ultimately leads to inflammation. Among these factors, lipophilic Malassezia yeasts may play a key role. Bacterial skin microbiota changes may also be involved in the pathogenesis of SD.^2-4
Current SD treatments consist of topical applications of antifungals and anti-inflammatory agents.⁵ Ketoconazole is a fungistatic agent, which limits Malassezia spp. growth, without inhibiting S. epidermidis or S. aureus.⁶ Selenium disulfide (SeS2-based shampoo has antifungal properties against Malassezia spp. and also inhibits Staphylococcus epidermidis growth in vitro.^6,7 The tested SeS2-based shampoo contains salicylic acid, known for its keratolytic activity, allowing to reduce flakes on the scalp.^5,8