Seborrheic Dermatitis

Definition

Seborrheic dermatitis in children is a chronic, relapsing inflammatory skin disorder characterized by erythematous, scaly, and sometimes greasy patches, commonly affecting the scalp (cradle cap), face, and diaper area.

Epidemiology

• Most common in infants under 3 months (cradle cap) and during adolescence
• Affects 1–5% of children outside the neonatal period
• Boys are slightly more affected than girls
• Often self-limiting in infancy but may persist or recur
• Incidence is higher in children with neurological or immunodeficiency disorders

Etiology

• Exact cause unknown; multifactorial
• Malassezia yeast colonization contributes to inflammation
• Sebaceous gland activity influences severity
• Genetic predisposition and immune response abnormalities
• Environmental factors: cold weather may exacerbate symptoms

Pathophysiology

• Overgrowth of Malassezia yeast on sebaceous-rich areas triggers local inflammation
• Increased sebum production enhances yeast proliferation
• Immune system responds with mild inflammation, causing erythema and scaling
• Disruption of the skin barrier may contribute to chronicity
• Inflammatory cytokines lead to erythema and scaling
• Relapsing course due to persistent colonization and sebaceous activity