Histology (Fig. 7.2)
The clinical appearance of the different stages of eczema mirrors their histology. In the acute stage, oedema in the epidermis (spongiosis) progresses to the formation of intraepidermal vesicles, which may co-alesce into larger blisters or rupture. The chronic stages of eczema show less spongiosis and vesication but more thickening of the prickle cell layer (acanthosis) and horny layers (hyperkeratosis and parakeratosis). These changes are accompanied by a variable degree of vasodilatation and infiltration with lymphocytes.