Spongiosis

Dissociation of the epidermis and the epithelial adnexal structures due to an intercellular edema with consecutive intraepithelial vesicle formation. Spongiosis is primarily observed in inflammatory dermatoses, e.g. in eczema diseases. It is caused by immigration of lymphocytes, but also by eosinophil and neutrophil granulocytes. In cases of low spongiosis, neighbouring keratinocytes are still connected to each other via intercellular bridges. If they are more strongly formed, these connections rupture and a larger intraepidermal cavity (spongiotic vesicle) is formed. In addition, the horny layer shows plasmatic inclusions with a parakeratosis mound. Spongiosis can also occur in the area of the adnexa (miliaria rubra, Fox-Fordyces disease, contact allergic eczema, suppurative folliculitis). In some dermatitides, epidermotropic eosinophilic or neutrophilic infiltrates also lead to a spongiotic reaction.

• Eosinophilic spongiosis: PUPPP, mycosis fungoides, erythema toxicum neonatorum, arthropod reaction, pseudolymphomas of the skin, incontinentia pigmenti, pemphigus vulgaris, pemphigoid, bullous, pemphigoid gestationis.
• Neutrophil spongiosis: tinea, psoriasis vulgaris, psoriasis palmaris et plantaris.

In most cases, spongiosis occurs in inflammatory processes of the skin, in rare cases epidermotropic neoplastic infiltrates can cause spongiotic reactions (e.g. in cutaneous T-cell lymphomas).