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not really a disease, but rather a physical sign of other diseases or conditions
Livedo reticularis – characterized by a regular network of livid discoloration of the skin
| • | caused by either vasoconstriction (e.g. neurohumoral reflexes) or by rheologic disturbances (e.g. polycythema rubra vera, polyglobulia, or hypercoagulopathies) |
Livedo racemosa – a livid mottling of the skin in an irregular broken netlike (lightning- shaped) pattern
| • | irregular pattern results from irregularly spaced vascular occlusions (e.g. vasculitis or Sneddon’s syndrome) |
Primary (Idiopathic):
| • | symmetric, well defined network |
| • | see nothing on biopsy but dilated vessels |
| • | may overlap with physiologic livedo (cutis marmorata) |
Secondary:
| • | more likely asymmetric and patchy (broken livedo) |
| • | emboli (e.g. cholesterol emboli, SBE, atrial myxoma) |
| • | anti phospholipid syndrome |
| • | thrombocythemia or polycythemia |
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| • | vasculitis/arteritis (especially PAN; also collagen vascular disease - dermatomyositis, LE) |
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Drugs: amantadine, quinine, quinidine, catecholamines
Polyarteritis nodosa
| • | usually livedo reticularis is accompanied by vasculitic nodules in this disease |
| • | livedo reticularis is associated with the “benign cutaneous polyarteritis” (uncommon to be seen in the PAN that causes severe systemic disease) |
sneddon’s syndrome
| • | = livedo reticularis with cerebrovascular lesions |
| • | antiphospholipid syndrome is one cause |
| 5. | collagen vascular disease |
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