Purpura
Basics
Description
Description
- Skin lesions caused 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
- Generally due to vasculitis:
Etiology
Etiology
- Nonpalpable purpura:
- Viral:
- Echovirus
- Coxsackie
- Measles
- Parvovirus B19
- Drugs:
- Acetaminophen
- Allopurinol
- Anticoagulants
- Aspirin
- Corticosteroids
- 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)
- Posttransfusion
- Viral:
- Palpable purpura:
- Viral:
- Epstein–Barr virus
- Cytomegalovirus
- Hepatitis B
- Bacterial:
- Streptococcal
- Gonococcus
- Meningococcus
- Pseudomonas
- Rickettsia rickettsii (Rocky Mountain spotted fever)
- 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. 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, “malignant chickenpox,” and “black measles” (both rare in the U.S.), coumadin necrosis
- Waldenstrom macroglobulinemia
- Protein C or S deficiency
- Wegener granulomatous
- Embolization: Cholesterol, crystal, thrombus (atrial myxoma, septic endocarditis, multiple myeloma)
- Viral:
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
Schaider, Jeffrey J., et al., editors. "Purpura." 5-Minute Emergency Consult, 6th ed., Lippincott Williams & Wilkins, 2020. Emergency Central, emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307303/all/Purpura.
Purpura. In: Schaider JJJ, Barkin RMR, Hayden SRS, et al, eds. 5-Minute Emergency Consult. Lippincott Williams & Wilkins; 2020. https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307303/all/Purpura. Accessed October 9, 2024.
Purpura. (2020). In Schaider, J. J., Barkin, R. M., Hayden, S. R., Wolfe, R. E., Barkin, A. Z., Shayne, P., & Rosen, P. (Eds.), 5-Minute Emergency Consult (6th ed.). Lippincott Williams & Wilkins. https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307303/all/Purpura
Purpura [Internet]. In: Schaider JJJ, Barkin RMR, Hayden SRS, Wolfe RER, Barkin AZA, Shayne PP, Rosen PP, editors. 5-Minute Emergency Consult. Lippincott Williams & Wilkins; 2020. [cited 2024 October 09]. Available from: https://emergency.unboundmedicine.com/emergency/view/5-Minute_Emergency_Consult/307303/all/Purpura.
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