Characteristics of ulcerated and non-ulcerated necrobiosis lipoidica

Background: Necrobiosis lipoidica (NL) is complicated by ulceration in up to 35% of cases. Methods: Retrospective study of patients with NL seen at our institution between January 1, 1992, and May 25, 2021, was conducted. Ulcerated NL (UNL, n = 83) and non-ulcerated NL (NUNL, n = 233) groups were compared. Results: Twenty-six percent (83/316) of patients with NL experienced ulceration. UNL was significantly more likely to be painful (52% vs. 36%, P = 0.01), was more likely to have a lesion-associated cutaneous malignancy (7% vs. 0%, P < 0.001), and had a larger median size (7 vs. 5 cm, P = 0.004) compared to NUNL. Vascular studies were performed on a subset of patients and revealed transcutaneous oxygen pressure (TcPO2) < 40 mm Hg in 53% and venous insufficiency in 62% with no significant differences between UNL and NUNL groups. In patients with unilateral ulceration, mean TcPO2 values (39.7 vs. 46.6 mm Hg), regional perfusion index <0.6 (29% vs. 14%), and TcPO2 < 40 mm Hg (43% vs. 14%) were worse in the ulcerated leg compared to the non-ulcerated leg, but these differences were not statistically significant. Conclusions: UNL was more likely to be painful, develop lesion-associated malignancy, and be larger in size compared to NUNL. There were no statistically significant differences in venous insufficiency, arterial Doppler/ankle brachial index, or TcPO2 values between UNL and NUNL patients, however, a significant portion of the cohort demonstrated abnormal vascular studies, particularly on TcPO2 and venous insufficiency testing.