Erosive adenomatosis of the nipple (EAN) is a rare benign entity that involves abnormal proliferation of the lactiferous ducts of the nipple and often presents with visible erosive lesions, erythema, or discharge. A 34-year-old female patient visited our clinic with erythematous patches and bloody discharge from the right nipple. Ultrasonography revealed a hypervascular lesion. A punch biopsy was performed, and histopathological examination confirmed the diagnosis of EAN. A 22-year-old female patient presented with a 4-year history of itchy erythematous eczematous patches with telangiectasia, crust, and bloody discharge in the areolar region. The punch biopsy results were consistent with those of EAN. The patient underwent total excision surgery. Herein, we report cases of EAN, which were difficult to differentiate from Paget's disease or nipple eczema, highlighting the need for clinicians to pay close attention. (Korean J Dermatol 2024;62(1):46∼49)