Lichen Amyloidosis (LA) is primary localized cutaneous amyloidosis, presenting pruritic, hyperkeratotic brown papules on the extensor surface. The association between AD and LA is thought to be close in previous studies. The anti-IL-4R alpha monoclonal antibody (Dupilumab) was approved for use in the treatment of adults with moderate to severe AD in Korea. Dupilumab is an receptor antagonist binding to the alpha subunit of the interleukin-4 receptor (IL-4R alpha). Through binding to IL-4R alpha, dupilumab inhibits signaling of both IL-4 and IL-13, the representative Th2 biomarkers. In addition to the treatment effects for AD during the treatment, we will introduce the unexpected effect of improving Lichen Amyloidosis. A thirty seven-year old male patient presented our clinic with generalized erythema, lichenification and flake as manifestation of AD, evaluated as EASI 16.2 and pruritus NRS 10. In addition to atopic lesions, lichen amyloidosis was observed on the legs. At 2 weeks after the initial administration of Dupilumab, systemic atopic lesions improved attaining EASI 50 and pruritus decreased to NRS 2. Furthermore, lichen amyloidosis lesions seen on the legs also showed marked improvement. Dupilumab is an emerging therapeutic agent for AD, and treatment cases are increasing in Korea. Herein, we report the unexpected effect of improving Lichen Amyloidosis in the treatment of Dupilumab, besides the treatment effect of AD.