Necrobiosis lipoidica: a descriptive study of 35 cases.

INTRODUCTION AND OBJECTIVES: Necrobiosis lipoidica (NL) is a chronic idiopathic granulomatous disease considered to occur in association with diabetes mellitus. Data on the frequency of this association, however, are inconsistent. Our aim was to retrospectively analyze the clinical characteristics of patients diagnosed with NL at our hospital and to investigate the association with diabetes mellitus and other diseases.

MATERIAL AND METHODS: We performed a chart review of all patients with a clinical and histologic diagnosis of NL treated and followed in the dermatology department of Hospital de Bellvitge in Barcelona, Spain between 1987 and 2013.

RESULTS: Thirty-five patients (6 men and 29 women with a mean age of 47.20 years) were diagnosed with NL in the study period. At the time of diagnosis, 31 patients had pretibial lesions. Thirteen patients (37%) had a single lesion at diagnosis, and the mean number of lesions was 3.37. Twenty-three patients (65.71%) had diabetes mellitus (type 1 in 10 cases and type 2 in 13). In 20 patients, onset of diabetes preceded that of NL by a mean of 135.70 months. The 2 conditions were diagnosed simultaneously in 3 patients. None of the 35 patients developed diabetes mellitus during follow-up. Six patients had hypothyroidism, and 4 of these also had type 1 diabetes.

CONCLUSIONS: NL is frequently associated with type 1 and 2 diabetes. Although diabetes tends to develop before NL, it can occur simultaneously.