Purpura is a topic covered in the 5-Minute Emergency Consult.

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Basics

Description

  • Skin lesionscaused by extravasation of blood into the skin or subcutaneous tissue
  • Can be caused by fragile capillaries, poor dermal support, and/or platelet dysfunction
  • The resultant lesions do not blanch completely with pressure (as seen when pressing down through a glass slide)
  • Nomenclature varies by the size of the lesions:
    • Petechiae (≤4 mm)
    • Purpuric lesions (5–10 mm)
    • Ecchymoses (>10 mm)
  • Color determined by depth and time of onset:
    • Red if superficial and recent onset
    • Purple if deep
    • Deep purple, brown, orange, or blue-green with later presentations
  • Nonpalpable purpura:
    • Simple hemorrhage or microvascular occlusion with ischemic hemorrhage
    • Generally due to a platelet disorder:
      • Diminished production
      • Altered distribution
      • Increased destruction
      • Abnormal function
  • Palpable purpura:
    • Generally due to vasculitis:
      • Autoimmune, small-vessel leukocytoclastic vasculitis
      • Hypersensitivity to various antigens
      • Formation of circulating immune complexes deposited in walls of postcapillary venules; activate complement that is chemotactic for polymorphonuclear leukocytes
      • Released enzymes damage vessel walls and cause leakage of blood
      • Vasculitic lesions may not be palpable in immunocompromised patients

Etiology

  • Nonpalpable purpura:
    • Viral:
      • Echovirus
      • Coxsackie
      • Measles
      • Parvovirus B19
    • Drugs:
      • Acetaminophen
      • Allopurinol
      • Anticoagulants
      • Aspirin
      • Digoxin
      • Furosemide
      • Gold salts
      • Lidocaine
      • Methyldopa
      • Nonsteroidal anti-inflammatory drugs
      • Penicillin G
      • Phenylbutazone
      • Quinidine
      • Quinine
      • Rifampin
      • Steroids
      • Sulfonamides
      • Thiazides
    • Nutritional deficiencies:
      • Vitamin K deficiency
      • Vitamin C deficiency (Scurvy)
    • Bone marrow disease
    • Hypersplenism
    • Idiopathic thrombocytopenic purpura (ITP)
    • Disseminated intravascular coagulation (DIC)
    • Thrombotic thrombocytopenic purpura
    • Liver or renal insufficiency
    • Thrombocytopenia (<50,000 plt/cc)
    • Thrombocytosis (>1,000,000 plt/cc)
    • Spiking elevations of intravascular pressure (childbirth, vomiting, paroxysmal coughing)
    • Hemophilia
    • Solar purpura (only on sun-exposed areas)
    • Post-transfusion
  • Palpable purpura:
    • Viral:
      • Echovirus type 9
      • Coxsackie
      • Hepatitis B
    • Streptococcal pharyngitis
    • Drugs:
      • Allopurinol
      • Anti-influenza vaccines
      • Cephalosporins
      • Gold
      • Heparin
      • Hydralazine
      • Iodides
      • Levamisole
      • Metoclopramide
      • Penicillin G
      • Phenylbutazone
      • Phenytoin
      • Quinidine
      • Quinine
      • Streptomycin
      • Sulfonamides
      • Thiazides
      • Ticlopidine
    • Malignancies
    • Autoimmune and connective tissue diseases
    • Gonococcus
    • Meningococcus
    • Pseudomonas (ecthyma gangrenosum)
    • Rocky Mountain spotted fever
    • In immunocompromised hosts: Candida, Aspergillus
    • Occlusion due to organisms living in vessels (generally immunocompromised hosts): Mucormycosis, aspergillosis, and disseminated strongyloidiasis
    • Occlusion due to microvascular platelet plugs (heparin necrosis)
    • Cold-related gelling or agglutination (cryoglobulinemia)
    • Local or systemic coagulation abnormalities: Scarlet fever, Vibrio vulnificus bacteremia; “malignantchickenpox” and “black measles” (both rare in US); Coumadin necrosis
    • Embolization: Cholesterol, crystal, thrombus (atrial myxoma, septic endocarditis, multiple myeloma)

Pediatric Considerations
  • Henoch–Schönlein purpura
  • Hemolytic uremic syndrome
  • Kawasaki disease
  • Neonatal:
    • Extramedullary erythropoiesis in rubella and cytomegalovirus (blueberry muffin baby)
    • Purpura fulminans (protein C and S deficiency)
    • Maternal ITP
    • Wiskott–Aldrich syndrome

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Citation

* When formatting your citation, note that all book, journal, and database titles should be italicized* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Purpura ID - 307303 Y1 - 2016 PB - 5-Minute Emergency Consult UR - https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307303/all/Purpura ER -