Dependent Rubor

Gunalp Uzun, M.D., and Mesut Mutluoglu, M.D.
N Engl J Med 2011; 364:e56June 30, 2011

A 45-year-old man was referred for evaluation of a painful and erythematous right foot. The patient had a 12-year history of type 2 diabetes mellitus and a 25-pack-year history of smoking. Examination of the right foot revealed several mottled, cyanotic toes and a dry, necrotic, eschar-covered wound in the fourth web space (Panel A). In the dependent position, the right foot was deeply erythematous, edematous, and cool to the touch (Panel B). A variation of Buerger's test was performed with the patient supine. Pallor of the foot developed rapidly with elevation of the foot above the level of the heart (Panel C). There was a recurrence of erythema only when the foot was lowered to a position below the examining table. Dependent rubor is suggestive of severe peripheral arterial disease. It occurs when dermal arterioles and capillaries no longer constrict in the presence of increased hydrostatic pressure. In this patient, the right posterior tibial and dorsalis pedis pulses were not palpable, and the bedside ankle–brachial index was abnormal at 0.4 (reference range, 0.9 to 1.3). The lower right anterior and posterior tibial arteries were significantly occluded on digital subtraction angiography, which confirmed a diagnosis of severe peripheral arterial disease. The patient was referred for surgical revascularization but was thereafter lost to follow-up.

Gunalp Uzun, M.D.
Mesut Mutluoglu, M.D.
Gulhane Military Medical Academy Haydarpasa Teaching Hospital, Istanbul, Turkey