Yes, skin changes can sometimes indicate internal cancers. For example, [paraneoplastic syndromes](href) are a group of rare disorders triggered by an immune response to a cancerous tumor. These can manifest as various skin changes, including dermatomyositis (red/purple rash on eyelids and over knuckles), acanthosis nigricans (dark, velvety patches in body folds), and erythema gyratum repens (rapidly moving, red, wood-grain-like rash).
