Black toes
A 36-year-old woman with type 1 diabetes went to see her doctor because 2 of her toes had turned black. She said that she noticed severe maceration between the first and second interspace approximately 6 weeks earlier. Subsequently, the toes changed color and became very painful. Two days ago, she noticed a foul odor from both toes. The patient reported smoking since the age of 13. There were no palpable pulses in the right foot.
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The family physician diagnosed peripheral arterial disease. PAD is an important factor leading to lower extremity amputation in patients with diabetes. Thirty percent of patients with diabetes who have an absent pedal pulse will have some degree of coronary artery disease.
PAD manifests in the lower extremity in 2 ways: macro- and microvascular diseases. Risk factors such as hypercholesteremia, hyperlipidemia, and hypertension are often associated with patients with PAD and, therefore, poor wound healing.
Dry, black eschar commonly begins distally at the extremities. There is a clear demarcation between healthy tissue and necrotic tissue. Pain may be present, and trauma is the most common etiology. Pulses may be nonpalpable. Smoking is commonly associated with this problem. Associated trophic skin changes include absent pedal hair and thin shiny skin.
Even in the presence of a palpable pulse, noninvasive studies (eg, arterial Doppler and pulse volume recordings) are important for baseline assessment of the patient’s blood flow. An angiogram is required to evaluate the possibility of revascularization. Radiographs may be necessary to rule out osteomyelitis.
This patient was admitted for IV antibiotics and revascularization was performed. Subsequently, the toes were partially amputated and the wounds healed without complication. Physicians attempted to help the patient to quit smoking, but were unsuccessful.
Photos and text for Photo Rounds Friday courtesy of Richard P. Usatine, MD. This case was adapted from: La Fontaine J, Shibuya, N. Dry gangrene. In: Usatine R, Smith M, Mayeaux EJ, et al, eds. The Color Atlas of Family Medicine. New York, NY: McGraw-Hill; 2009:912-913.
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