Eczema. Artwork of a section through the epidermis of human skin affected by eczema. The boy's face shows the characteristic itchy pink rash on the skin's surface, accompanied by small, fluid- filled vesicles that weep and become crusted. Many factors can trigger the rash, but all tend to produce the same histological features. Fluid accumulates in the epidermis (folded pink layer), resulting in separation of the cells (spongiosis). Clumps of epidermal cells disintegrate to form vesicles (yellow). Blood vessels in the underlying dermis are dilated. The yellow layer at the bottom is subcutaneous fatty (adipose) tissue.