Update on clinical and laboratory features in necrobiosis lipoidica: a retrospective multicentre study of 52 patients.

Necrobiosis lipoidica (NL) is a rare granulomatous disorder of unknown etiology which can manifest in ulcerative skin lesions and is widely recognised in association with diabetes mellitus. Our aim was to improve knowledge about the epidemiology and clinical course of NL and evaluate treatment approaches. This multicentre retrospective study covered data from 52 patients with NL of the lower leg, treated between 2006 and 2011. Data from three German dermatological centres were analysed. Twelve men and 40 women, aged 15 to 87 years, were evaluated with regard to epidemiological data, ulcerations, co-morbidities, laboratory values and treatment options. NL was significantly more frequent in women (76.9%). Ulceration of NL was observed in 25% of all patients and in 37.5% with concomitant diabetes mellitus. 88% received topical treatment with corticosteroids, 56% compression therapy of the lower legs, 42% UV-phototherapy and 29% topical calcineurininhibitors. Systemic therapies were also used occasionally. Our data indicate that female sex, middle age and endocrine disorders like diabetes mellitus are characteristics of NL patients. As new aspects, we found an accumulation of thyroidal dysfunction (13%) and that ulcerations are predominantly in males (58%). Associations with co-morbidities may become clearer in prospective studies of larger cohorts. Topical steroids, calcineurin inhibitors, compression therapy and phototherapy seem to be the basis therapies although our evaluation showed that standardized guidelines are missing. More experimental therapeutic options, like biologicals, photodynamic therapy or the use of fumaric acid esters, should be assessed for efficacy and safety by large, randomized, controlled trials.