The three-dimensional histological architecture of pustulosis palmo-plantaris

Using computer reconstruction techniques, it is possible to study and understand the three-dimensional architecture of the histo-pathological changes in pustulosis palmo-plantaris (PPP). In PPP vesicles and pustules develop. As the vesicles move upwards, they may gain contact with a granulocytic lake above them. Through the roof of the vesicle, granulocytes then break into the vesicle thereby changing it into a pustule. The blood vessels in PPP exhibit a bulbous vascular network at the epidermal end of the dermal papillae. At lower levels, the capillaries may form loops and arches. It is suggested that this special architecture of the vascular system produces a marked retardation of the blood flow in the tips of the dermal papillae, allowing a longer contact of the blood with the capillary wall. The granulocytes can therefore easily immigrate.