Current Understanding of Seborrheic Dermatitis: Epidemiology, Burden of Disease, and Pathophysiology.

Seborrheic dermatitis is a common chronic dermatosis predominantly affecting sebum-rich areas. The diagnosis of seborrheic dermatitis can be challenging due to its clinical resemblance to other dermatoses. Seborrheic dermatitis can significantly impact quality of life, particularly in those with pruritus and dyspigmentation involving the facial region. The pathogenesis of seborrheic dermatitis is complex, and while its etiology is not yet fully understood, current evidence points to a complex interplay between 3 key factors: skin microbiome dysbiosis involving Malassezia spp. overgrowth and alterations in bacterial composition, dysregulated inflammatory responses in the skin, and skin barrier dysfunction. This review provides an updated overview of seborrheic dermatitis epidemiology, burden of disease, and pathophysiology, highlighting the integral roles of microbiome, inflammation, and skin barrier dysfunction in its pathogenesis. This is the first in a series of 3 reviews, each addressing different aspects of seborrheic dermatitis, including its epidemiology, diagnosis, and treatment considerations.