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The term “spongiotic dermatitis” refers to a large group of inflammatory disorders that share the histopathologic finding of spongiosis, characterized by impairment of cohesion between epidermal keratinocytes and intercellular edema (Fig. 2-1 and Table 2-1). Spongiosis is the hallmark of eczematous dermatitides but can be seen in a variety of other skin conditions (Table 2-2). Both T lymphocytes and keratinocytes are thought to play major roles in the pathogenesis of spongiotic dermatitis.1,2 Skin-infiltrating T cells damage the epidermis by releasing pro-inflammatory cytokines and induce keratinocyte apoptosis through “killer molecules.”1,2 There is subsequent cleavage of adhesion molecules, including E-cadherin, on keratinocytes.1,2 Accumulation of extracellular fluid results in widening of the spaces between keratinocytes, causing the epidermis to resemble a sponge histologically.1,2
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Other terms used to refer to these diseases include “eczema,” “eczematous dermatitis,” and simply “dermatitis.” The clinical appearance of the spongiotic dermatoses can vary significantly, depending on the duration, etiology, and location of the lesions, the presence of ...