[Lichen planus: fundamentals, clinical variants, histological features, and differential diagnosis]

Lichen planus (LP) is a relatively common inflammatory skin disease in dermatological practice. The typical presentation of LP is usually diagnosed clinically. Less common variants such as LP inversus, atrophic LP, the palmoplantar manifestation or childhood LP may pose diagnostic difficulties so that a biopsy is taken to confirm the diagnosis. Differentiation from LP-like drug eruption may be challenging and biologicals have to be considered as triggers. Etiology and pathogenesis of LP are discussed based on recent literature. Finally, an overview of therapeutic options for different variants of the condition includes most recent approaches to treatment.