Cutaneous manifestations of systemic disease: pattern approach

At a glance

• The skin often shows internal disease first: dermatomyositis before the ovarian cancer, acanthosis nigricans before the diabetes, palpable purpura before the glomerulonephritis.
• Work in order: morphology, distribution, timing, then the reaction pattern. A reaction pattern narrows the cause list far more than the organ you suspect.
• Skin disease is also a cause of death and disability: skin failure in erythroderma and TEN, skin cancer, and the cardiovascular and mental health burden of chronic inflammatory disease.