Livedo Reticularis

Definition: Persistent net-like violet skin discolouration.

It represents the pattern of venous channels at the periphery of arterial cones in the skin. Must be distinguished from cutis marmorata which is identical in appearance but occurs only in response to cold. Cutis marmorata is extremely common in babies and is entirely physiological. Cutis marmorata telangiectatica congenita is a congential skin disease characterised by livedo reticularis with ulceration.

Caused by:

• Reduced skin blood flow:
  • arteriolar obstruction,
    1. arteritis (SLE, RhA, PAN, CREST, dermatomyositis, &c.)
    2. arteriosclerosis
    3. Raynaud's
    4. endarteritis obliterans (cryoglobulinaemia, crystal, or immune complex deposition)
    5. emboli:
       • gas emboli:
         • ventilator barotrauma
         • decompression sickness ('the bends')
         • carbon dioxide arteriography
       • crystal emboli:
         • cholesterol emboli syndrome (aortic manipulation, radiological procedures)
    6. intravascular crystallisation:
       • hyperoxaluria (calcium oxalate)
       • hyperparathyroidism/pseudohypoparathyroidism (calcium hydroxyapatite)
  • venular outflow obstruction,
    • right heart failure
  • blood hyperviscosity.
    • lymphoproliferative disorder (via hyperproteinaemia, polycythaemia, paraneoplastic vasculitis)
    • Waldenstrom's Macroglobulinaemia
• Drugs:
  • amantadine
  • catecholamines
  • bismuth
  • quinine
  • minocycline
• Miscellaneous:
  1. Primary idiopathic
  2. Hereditary Protein C deficiency (type I)
  3. Antithrombin III deficiency
  4. Sneddon Syndrome (livedo reticularis and strokes--positive for anti-endothelial cell antibodies)
  5. acute parvovirus B19 infection