Lichen Planus After Denosumab

Lichenoid reactions have been described as a side effect of several drugs. Here we describe the development of lichen planus (LP) of the mammilla following off-label use of denosumab in an adolescent patient with mono-ostotic fibrous dysplasia. Lichen planus is considered an autoimmune disorder. Since receptor activator of nuclear factor kappa & UBeta; ligand (RANKL), the target of denosumab action, has regulatory function in the immune system, it is feasible, that LP may be caused as part of an immunological dysregulation.