II. Pathophysiology

  1. Capillary leak at epidermal ridge

III. Signs

  1. Red or brown Nail Longitudinal Band 1-3 mm long
    1. Typically start as red and then transition to brown or black
  2. Involves nail bed (not nail plate)
  3. Lines persist despite pressure applied to the nail
    1. Lines are due to blood that has leaked from the vasculature

IV. Causes

  1. Subacute Bacterial Endocarditis (classic)
    1. Only occurs in 15% of endocarditis cases
  2. Local Trauma (common cause)
  3. Psoriasis
  4. Onychomycosis
  5. Trichinosis
  6. Other conditions include renal, pulmonary and endocrine conditions

VI. References

  1. Degowin (1987) Diagnostic Exam, Macmillan, p. 697
  2. Tully (2012) Am Fam Physician 85(8): 779-87 [PubMed]

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