Fumaric acid esters in necrobiosis lipoidica:: results of a prospective noncontrolled study

Background Necrobiosis lipoidica (NL) is an uncommon granulomatous skin disease with association to diabetes mellitus. To date, no proven effective therapy for NL has been implemented. The standard treatment is topical application of corticosteroids, but numerous agents have been reported for NL, with varying degrees of success. In recent case reports, fumaric acid esters (FAE) have been reported to be effective in granulomatous skin diseases such as granuloma annulare, cutaneous sarcoidosis and NL. Objectives We sought to investigate the efficacy of FAE in a larger number of patients with NL. Methods Eighteen patients with histopathologically proven NL were consecutively recruited into a prospective noncontrolled study. Dosage of FAE was given according to the standard therapy regimen for psoriasis. FAE were administered for at least 6 months. The treatment outcome was evaluated by means of clinical and histological scoring and 20-MHz ultrasound assessments. Results Three patients discontinued therapy with FAE, while the remaining 15 patients finished the study. After a mean +/- SD treatment period of 7.7 +/- 2.9 months, a significant (P < 0.001) decrease in the mean +/- SD clinical score, from 7.4 +/- 1.8 at the beginning to 2.5 +/- 1.3 at the end of therapy, was observed. Significant clinical improvement of NL was accompanied by significant (P = 0.019) increase of dermal density as assessed by means of 20-MHz ultrasound, and significant (P = 0.011) reduction of the histological score. Adverse effects were moderate and consisted mainly of gastrointestinal complaints and flushing. During follow-up of at least 6 months, clinical outcome remained stable in all patients. Conclusions The results of this study demonstrate that FAE are beneficial and safe in the treatment of patients with NL.