Background: Cholesterol embolization syndrome (CES) is an increasingly reco
gnized cause of acute renal insufficiency, which must be differentiated fro
m other forms of systemic vasculitis by histologic examination of biopsies
from involved organs. This report describes the optimal methods for detecti
on and biopsy of areas of skin involved with livedo reticularis to confirm
the diagnosis of CES. Methods: This report describes 8 patients with unexpl
ained acute renal insufficiency in whom the diagnosis of CES was suspected
based on their clinical history. Results: A detailed skin examination perfo
rmed in both supine and upright postures demonstrated the presence of previ
ously unrecognized livedo reticularis, which was more evident during uprigh
t posture in all subjects. In 2 subjects, questionable areas of livedo reti
cularis noted in supine posture became readily demonstrable during upright
posture. Livedo reticularis was apparent only during upright posture in 2 s
ubjects. Biopsies of areas of skin involved with livedo reticularis demonst
rated cholesterol emboli in 6 of 8 patients and were normal in the remainin
g 2 patients. One patient progressed to end-stage renal disease and one was
lost to follow-up. In the remaining 6 patients, renal insufficiency initia
lly progressed but did not require dialytic therapy. Renal function returne
d to baseline levels and livedo reticularis resolved without recurrence in
these patients. No subjects developed clinical or laboratory evidence of sy
stemic vasculitis. Conclusions: Livedo reticularis is a common but often un
recognized finding in CES that may not be evident during routine examinatio
n performed in the supine posture. Deep cutaneous biopsy of areas of livedo
reticularis can be safely used to confirm the presence of cholesterol embo
li, thus avoiding the increased morbidity of biopsy of either pregangrenous
skin lesions or visceral organs. Many patients with CES regain renal funct
ion during long-term follow-up.