ABSTRACT
This chapter focuses on the classification, causes, clinical manifestations, differential diagnosis, histology, treatment, and prognosis of seborrheic dermatitis in both its adult and infantile forms. A classification system divides infantile seborrheic dermatitis into true seborrheic dermatitis, psoriasiform seborrheic dermatitis, and erythrodermic seborrheic dermatitis. Adult seborrheic dermatitis typically presents between the ages of 12 and 45 years, with peaks in adolescence and in those over 50. The differential diagnosis of seborrheic dermatitis in adults and infants centers on conditions that cause erythema and scaling. In some instances seborrheic involvement simulates guttate psoriasis. Psoriasis lesions demonstrate neutrophils in the horny layer, thinning of the suprapapillary plates, and tortuous capillaries in the dermal papillae – findings not generally seen in seborrheic dermatitis. Histopathology demonstrates regular or irregular acanthosis, variable focal spongiosis with exocytosis of mononuclear cells, and occasional neutrophils. Terbinafine has proven to be an effective treatment for seborrheic dermatitis.
