Derm Dx: Asymptomatic dermatitis that feels like sandpaper

A 29-year-old woman presents with a rash on her arm that the patient reports has been there “for as long as I can remember.” The dermatitis is asymptomatic, but the patient finds it annoying from a cosmetic standpoint. She states that her mother and sister both have a similarly distributed rash, but their rashes are not as prominent. Application of ...