RT Book, Section A1 Holland, Kristen E. A1 Boulos, Scarlett A2 Kline, Mark W. SR Print(0) ID 1182905132 T1 Disorders of the Epidermis T2 Rudolph's Pediatrics, 23e YR 2018 FD 2018 PB McGraw-Hill Education PP New York, NY SN 9781259588594 LK accesspediatrics.mhmedical.com/content.aspx?aid=1182905132 RD 2024/10/05 AB Primary skin diseases that principally affect the epidermis may be categorized as either a dermatitis or a papulosquamous disorder. Dermatitis commonly denotes inflammation of the epidermis. Eczema generically denotes edema within the epidermis. Many primary dermatitides are eczematous in nature, although the term eczema is often misused interchangeably for atopic dermatitis (AD). In its mildest or chronic form, edema is seen histopathologically as prominent, tooth-like interconnections between keratinocytes (spongiosis). With more intracellular fluid accumulation, intraepidermal vesicles are formed. Vesicles are often subclinical in subacute or chronic eczemas where edema is mild but present as grossly evident vesicles and bullae in acute eczemas. Papulosquamous eruptions are characterized by the presence of erythematous papules or plaques with overlying scale. While eczematous processes clinically manifest with weeping or crusting, papulosquamous disorders are associated with little to no edema and thus clinically tend to be dry.