Forty-one biopsy specimens, taken from the
ulcer-bearing skin of 41 legs of 21 patients attending the
varicose vein clinic, were selectively stained for
fibrin with
phosphotungstic acid haemotoxylin before being blindly assessed,. Layers of
fibrin were found surrounding the dermal capillaries in all 26 legs with
lipodermatosclerosis. None of the specimens from the 15 legs with clinically normal skin contained
fibrin. There was also an increased number of dermal capillaries cut in cross section per high powered field in 24 of the 26 legs with
lipodermatosclerosis compared with two of the 15 legs with normal skin (p less than 0.001). The mean reduction in foot vein pressure during exercise was significantly less in the 26 limbs with pericapillary
fibrin than in the other 15 limbs (p less than 10(-6).
Lipodermatosclerosis is synonymous with pericapillary
fibrin deposition and is associated with, and probably secondary to, both a persistently raised venous pressure and an increase in the size of the dermal capillary bed. This extravascular deposition of
fibrin probably stimulates tissue
fibrosis and blocks the diffusion of
oxygen to the overlying epidermis, producing cellular death and venous ulceration.