Scalp Seborrheic Dermatitis: What We Know So Far.

Scalp seborrheic dermatitis (SSD) is a prevalent chronic, relapsing inflammatory skin disease. The etiology is related to sebum production, bacterial proliferation - Staphylococcus sp., Streptococcus, and M. restricta - and host immunity factors - NK1+, CD16+ cells, IL-1, and IL-8. Trichoscopy features include mostly arborizing vessels and yellowish scales. New trichoscopic findings were described to guide the diagnosis as dandelion vascular conglomerate, "cherry blossom" vascular pattern, and intrafollicular oily material. Antifungals and corticosteroids constitute the essential therapy, but new treatments have been described. This article aims to review and discuss the etiology, pathophysiology, trichoscopy, histopathologic findings, main differential diagnoses, and therapeutic options of SSD.