Petechiae and Purpura
John L. Smith
Purpura are the visible extravasation of blood into the skin or mucous membranes. Petechiae are purpura less than 2 mm in diameter and ecchymoses are greater than 1 cm in diameter.
Approach
Purpura are a sign of another illness or pathologic process. After initially ruling out emergent or life-threatening disorders, which are the norm in newborns and occasionally with infectious causes, a specific cause is sought. Purpuric rashes are secondary to a quantitative or qualitative platelet abnormality, coagulation disorder, or congenital or acquired vascular disorder.
History
A. Have there been any recent illnesses? Henoch-Schönlein purpura is associated with a preceding upper respiratory infection in 60% to 75% of cases (1). Streptococcus pneumoniae is the most commonly cited organism. Various other infections may be responsible for thrombocytopenias and vasculitis.
B. Has there been any recent medication usage? Quinidine, quinine, sulfa, aspirin, and many other medications have been associated with purpuric lesions.
C. Are there any additional symptoms, such as abdominal or joint pain, or gastrointestinal symptoms including changes in stool characteristics? Henoch-Schönlein purpura is associated with all of these; abdominal pain is noted in 40% to 80% of patients (1).
D. Is there a history of heavy menses or mucous membrane bleeding? Coagulation abnormalities such as von Willebrand’s disease (present in 0.5% to 1% of the population) or platelet abnormalities are most likely (3) (Chapter 11.5).
E. Is there a history of prior transfusions or heavy bleeding with previous operations?
F. Are there risk factors for a history of liver disease? There may be impaired synthesis of coagulation factors.
G. Has there been a similar rash in the past? A long history of purpura may be present in idiopathic thrombocytopenic purpura (ITP) as it tends to be a chronic course with an insidious onset in adults.
H. If the patient is a newborn, was there maternal illness, drug exposure, maternal ITP, or was vitamin K given? Hemorrhagic disease of the newborn develops on the second or third day of life. The most common causes of purpura fulminans in the neonatal period are congenital deficiencies of proteins C and S (1).
Physical examination
A. General and vital signs. Does the patient appear toxic or unstable? Considerations would include meningococcemia, Rocky Mountain spotted fever, disseminated intravascular coagulation (DIC), sepsis from Staphylococcus aureus, or thrombotic thrombocytopenic purpura.
B. Skin. Purpura should not blanch or only partially blanch with pressure. Petechiae are generally indicative of a quantitative or qualitative platelet abnormality. These nonpalpable petechiae may be caused by thrombocytopenia, which is either congenital or acquired (Chapter 16.7). The acquired thrombocytopenia can be caused by decreased platelet production as seen with viral infections, B12 or folate deficiency, iron deficiency, or a drug reaction. It is also seen with evidence of platelet destruction as present in ITP, connective tissue disease, leukemia, drugs, DIC, and thrombotic thrombocytopenic purpura. Abnormal platelet function is seen with aspirin ingestion, kidney and liver dysfunction, and in the thrombocytosis seen with myeloproliferative disorders. Significant straining with the Valsalva maneuver can cause petechiae. Lastly, the chronic pigmented purpura are the brown-orange spots occasionally seen on the lower extremities of adults. Schamberg’s disease is the most frequently seen and well known of the group. In these disorders, petechia are often intermixed with the pigmentation.
Ecchymoses are usually associated with coagulation disorders (e.g., in hemophilia, von Willebrand’s disease, anticoagulant usage, DIC, and vitamin K deficiency). Also responsible for ecchymoses are weakened connective tissue with less protection for vessels, as seen in senile purpura; glucocorticoid excess; vitamin C deficiency; and congenital disorders, such as Ehlers–Danlos syndrome.
Palpable purpura are usually secondary to a vasculitis. The causes are many and include hypersensitivity vasculitis to drugs; infections, including viral, rickettsial, and bacterial illnesses; cryoglobulinemias, such as Waldenström’s; and granulomatous causes, such as Wegener’s granulomatosis.
Testing
A. Test selection. Initial laboratory: Complete blood count (CBC), platelet count, peripheral smear, prothrombin time (PT), activated partial thromboplastin time (APTT), and possibly a bleeding time (3). If the lesions appear vasculitic, consider a sedimentation rate and C-reactive protein determination. Serum creatinine and urinalysis can be ordered to screen for renal involvement. In vasculitis, the laboratory findings are often nonspecific and a skin biopsy for histology is employed (2).
B. Significance of test results
1. Isolated thrombocytopenia: most often ITP in nonpregnant women. Without atypical features, no follow-up laboratory study is recommended (4).
2. Isolated, increased APTT: low levels of factors VIII, IX, XI. Follow-up studies: factor VIII level and von Willebrand’s factor assay and activity.
A slightly increased APTT and slightly decreased factor VIII are consistent with von Willebrand’s disease. A very prolonged APTT and very low factor VIII is consistent with an acquired factor VIII inhibitor (3).
3. Thrombocytopenia with increased PT, APTT: consider DIC and liver failure. Follow-up study: d-dimer, fibrinogen, fibrin degradation products.
In newborns with purpura, evaluation for sepsis, serologies for the TORCH syndrome (acronym for Toxoplasmosis, Other infections, Rubella, Cytomegalovirus infection, and Herpes simplex), and coagulation factors are also recommended. Proteins C and S activities are also indicated in purpura fulminans (diffuse ecchymoses that become bullous and necrotic); neutropenia or abnormal neutrophils may indicate leukemia. Other laboratory tests when evaluating vasculitis can include complement levels, antinuclear antibody, and cryoglobulins.
Diagnostic assessment (4)
With petechiae resulting from lone thrombocytopenia, ITP may be difficult to differentiate from pregnancy-induced thrombocytopenia (which tends to be milder), viral infection, or drugs. ITP is designated if no other clinically obvious cause is noted.
Thrombotic-thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS) are seen in many clinical situations, including pregnancy, cancer, infections, chemotherapy, and so on. Signs include the pentad of fever, thrombocytopenia, microangioipathic hemolytic anemia, hemorrhage (including purpura), and neurologic abnormalities. Because of serious consequences, the diagnosis should be considered if thrombocytopenia and fragmented red blood cells are seen on the peripheral smear. TTP-HUS has a normal PT, APTT, and d-dimer as opposed to DIC.
In regard to coagulation factor abnormalities, hemophilia A and B can cause increased bruising and ecchymoses but not nearly as frequently as von Willebrand’s disease. Children being investigated for nonaccidental bruising should be evaluated for coagulation disorders with a CBC, platelet count, PT, APTT, and a bleeding time. With the sudden onset of large ecchymoses and hematomas in an adult with normal platelets, an acquired factor VIII deficiency (autoantibody) should be investigated in cases of a prolonged PT, APTT.
In newborns, a blueberry muffin baby (from extramedullary hematopoiesis) may appear purpuric, and this condition must be differentiated from purpura fulminans secondary to protein C or S deficiency, or sepsis.
Vasculitis causing palpable purpura in children is most common with Henoch–Schönlein purpura. In connective tissue diseases, purpuric lesions are usually a secondary finding.
The causes of purpuric lesions are many. A thorough history and physical examination, along with some basic laboratory studies and an occasional skin biopsy, are all that is needed to establish a likely diagnosis.
References
1. Baselga E, Drolet BA, Esterly NB. Purpura in infants and children. J Am Acad Dermatol 1997;37:673–705.
2. Cuttica RJ. Vasculitis in children: a diagnostic challenge. Curr Probl Pediatr 1997 27:309–317.
3. Loserh JM. Screening and diagnosis of coagulation disorders. Am J Obstet Gynecol 1996;175:778–783.
4. Diagnosis and treatment of idiopathic thrombocytopenic purpura: Recommendations of the American Society of Hematology. The American Society of Hematology ITP Practice Guideline Panel. Ann Intern Med 1997;126:319–326.
Book Source Details
- Book Title: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter
- Author(s): Robert B. Taylor (editor)
- Year of Publication: 2000
- Copyright Details: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, Copyright © 2000 Lippincott Williams & Wilkins.
Other Book Chapters Related to Ecchymosis
Read excerpts from these other book chapters related to Ecchymosis:
Medical Books Excerpts
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- "In a Page: Signs and Symptoms" (2004)
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- "In A Page: Pediatric Signs and Symptoms" (2007)
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- "In A Page: Pediatric Signs and Symptoms" (2007)
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- Purpura
- "Handbook of Signs & Symptoms (Third Edition)" (2006)
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- "Professional Guide to Signs & Symptoms (Fifth Edition)" (2006)
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- "Signs & Symptoms: A 2-in-1 Reference for Nurses" (2007)
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- "Nursing: Interpreting Signs and Symptoms" (2007)
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Copyright Details: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, Copyright © 2008 Williams & Wilkins.
More About Causes of Ecchymosis
» Next page: Purpura/Petechiae/Excessive Bleeding (Field Guide to Bedside Diagnosis)
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