The patient's skin findings are most consistent with a venous stasis ulcer. Venous stasis ulcers are commonly found on the lower extremities, particularly on or near the medial malleoli. They often occur in patients with recurrent bouts of stasis dermatitis, which is an eczematous rash on the lower legs associated with impaired venous drainage of the lower extremities caused by venous insufficiency, or by chronic peripheral edema of any cause. Venous stasis leads to changes in vascular permeability with stretching of the skin and loss of integrity of the dermal barrier. Initial changes involve development of dermatitis, seen as dark discoloration (postinflammatory hyperpigmentation) and “woody” induration known as lipodermatosclerosis. Impaired skin function in areas of venous stasis may also lead to breakdown of the dermal barrier with development of ulceration. Venous stasis ulcers tend to be shallow rather than deep. They may be asymptomatic or quite tender.
Arterial ulcers also occur on the lower extremities, but in contrast to venous stasis ulcers, they are not surrounded by stasis dermatitis changes or lipodermatosclerosis. They tend to be more demarcated than venous stasis ulcers and are often painful. The surrounding skin tends to be white or erythematous, and there is a loss of leg hair. These ulcers typically occur in the setting of peripheral atherosclerotic disease, with diminished pedal pulses and impaired capillary refill.
Neuropathic ulcers arise from repetitive trauma in patients with a history of sensory loss in the lower extremities. The ulcers are well-demarcated, often quite deep, and lack surrounding inflammation; they develop on pressure points or other areas where recurrent trauma may occur. They are most commonly seen in patients with peripheral neuropathy associated with diabetes mellitus.
Pyoderma gangrenosum is an uncommon inflammatory process that often occurs on the pretibial aspects of the lower legs and is often associated with an underlying systemic disease, such as inflammatory bowel disease or monoclonal gammopathy. The ulcers are well-demarcated, often very deep and painful, and show progression of the ulcer under the overlying skin (undermined borders). The ulcers tend to lack surrounding evidence of stasis, as is present in this patient.
