The dual roles of T cells and keratinocytes in seborrheic dermatitis: a narrative review.

Seborrheic dermatitis (SD) is a recurrent inflammatory skin disease primarily affects sebaceous gland-rich areas, particularly the scalp. Its characteristic clinical manifestations including dandruff, greasy crusting, and pruritus. These recurrent symptoms frequently impose significant psychological distress on patients. SD is classically associated with sebum secretion, Malassezia colonization, and individual susceptibility, whereas the critical roles of keratinocyte barrier dysfunction and T cell-mediated inflammation also constitute components in disease progression. In this review, we elucidate the mechanistic interplay between keratinocytes and T cells in SD development, proposing that their functional imbalance serves as a key driver of pathogenesis. We also systematically evaluate relevant therapies targeting keratinocytes and T cells, aiming to offer novel insights into SD pathophysiology and treatment.