Purpura

Background

• Palpable petechiae and purpura are a result of either perivascular inflammation (vasculitis) or infection.
• Non-palpable petechiae usually occur in low platelet states such as ITP and DIC

Rash Red Flags

• Fever
• Toxic appearance
• Hypotension
• Mucosal lesions
• Severe pain
• Very old or young age
• Immunosuppressed
• New medication

Clinical Features

Palpable Purpura

Both petechia and purpura do not blanch

• Purpura subdivided into:
  • <2mm of hemorrhage: petechiae
  • >2mm of hemorrhage: ecchymoses

Differential Diagnosis

Petechiae/Purpura (by cause)

• Abnormal platelet count and/or coagulation
  • Septicemia
  • Idiopathic thrombocytopenic purpura (ITP)
  • Hemolytic uremic syndrome
  • Leukemia
  • Coagulopathies (e.g. hemophilia)
  • Henoch-Schonlein Purpura (HSP)
  • Acute hemorrhagic edema of infancy (AHEI)
• Hypersensitivity vasculitis
• Primary vasculitides
  • Wegener's
  • Microscopic polyangiitis
  • Eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome)
• Secondary vasculitides
  • Henoch-Schonlein purpura
  • Connective tissue disorder
    • Systemic lupus erythematosus
  • Scurvy
  • Infectious disease
    • Hepatitis B
    • Hepatitis C
• Trauma

Differential by Findings

• Febrile, toxic
  • Palpable
    • Meningococcemia
    • Disseminated gonococcal infection
    • Endocarditis
    • Rocky mountain spotted fever
    • HSP
  • Non-palpable
    • Purpura fulminans
    • DIC
    • TTP
• Afebrile, nontoxic
  • Palpable
    • Autoimmune vasculitis
  • Non-palpable
    • ITP

See Also

• Rashes