Correspondence (letter to the editor): Fumaric Acid Esters as an Additional Systemic Therapy Option

In symptoms that often prove so refractory to treatment and are so vexing for patients, for which no gold standard treatment exists (1), we would like to additionally mention the use of fumaric acid esters. Before 2005, a small working group around Professor Hagedorn conducted an uncontrolled open-label study with fumaric acid esters in 12 patients with recurrent benign aphthous ulcers (2). Only in one case did the treatment have to be stopped because of adverse effects; three patients experienced complete remission and eight an improvement of their symptoms owing to longer recurrence-free intervals, more rapid healing, or a reduction in the number of aphthous ulcers. Furthermore, several hypotheses were introduced regarding the mechanism of action of fumaric acid esters in recurrent benign aphthous ulcers.

The treatment back then was found to be relatively well tolerated (this was partly due to the low dosage—compared with that required to treat psoriasis—of 120–240 mg fumaric acid esters a day), and a number of otherwise treatment refractory patients responded well and experienced long term benefits.

Of course this is again all done off label. The long term safety of fumaric acid esters taken daily for many years was pointed out only in recent publications on the treatment of psoriasis vulgaris and enables the treating physician to balance risks and benefits. For this reason, fumaric acid esters represent a further helpful treatment option in otherwise refractory cases of recurrent benign aphthous ulcers—something that I wanted to draw readers’ attention to, in spite of the low evidence level of the early study.