The effect of levamisole in the treatment of recalcitrant recurrent erythema multiforme major: An observational study

Background: Erythema multiforme major (EMM) is an immune-mediated mucocutaneous eruption mostly triggered by herpes simplex virus (HSV) infection. A vicious circle of recurrence may be developed due to HSV reactivation and prolonged use of systemic corticosteroids to control EMM. Levamisole is an immunomodulator and has been applied to prevent relapses of recurrent HSV infection. Objective: To evaluate the clinical efficacy and safety of levamisole in patients with recalcitrant recurrent EMM. Methods: We enrolled 23 patients with recurrent EMM treated with levamisole and 24 controls, and analyzed the demographics, treatments and outcomes. Results: Patients with recurrent EMM for years (mean 3.99 ± 2.71) showed significantly reduced recurrences after various durations of levamisole treatment (recurrences after and before treatment: 3.98 ± 1.04 vs 6.75 ± 1.45 times per year, p = 1.33x10⁻⁸). The recurrences of EMM also significantly reduced after levamisole treatment comparing to that of patients without levamisole treatment (p = 3.77x10⁻⁹). No patient was reported to have severe side effects during or after levamisole treatment. Conclusions: Levamisole was effective in reducing recurrences of recalcitrant recurrent EMM and can thus be considered an alternative or add-on therapy for this disorder.