Fully developed

Sparse superficial perivascular infiltrate of mostly lymphocytes
Slight edema of the papillary dermis
Dilated tortuous capillaries in dermal papillae
Slight epidermal hyperplasia
Some mitotic figures in keratinocytes above the epidermal basal layer
Spongiosis in company with a few lymphocytes in discrete foci in the lower part of the epidermis
Spongiform and subcorneal pustules within the epidermis of some lesions
Hypergranulosis in some foci
Mounds of parakeratosis with neutrophils at their summits staggered within the stratum corneum, sometimes beneath the retained original cornified layer with its basket-woven configuration