Hospital Medicine

Purpura/ Petechiae

I. Problem/Condition.

Purpura is a small hemorrhage into the skin, mucous membrane or serosal surface. Because purpura is caused by extravasation of blood from the vasculature into the skin it does not blanch with pressure.

Depending on their size, purpuric lesions are classified as:

  • petechiae -- < 5 mm

  • purpura -- 5-9 mm

  • ecchymoses -- > 9 mm

II. Diagnostic Approach.

A. What is the differential diagnosis for this problem?

The differential diagnosis to purpura can be divided into platelet disorders, vascular factors and coagulation factor deficiencies.

  1. Platelet disorders

    1. Thrombocytopenia

      1. Idiopathic thrombocytopenic purpura (ITP)

      2. Hemolytic-uremic syndrome (HUS)

      3. Thrombotic thrombocytopenic purpura (TTP)

      4. Disseminated intravascular coagulopathy (DIC)

      5. Medications

      6. Infection

      7. Malignancy

      8. Splenomegaly

    2. Platelet dysfunction

      1. Medications

      2. Uremia

  2. Vascular factors

    1. Vasculitis

      1. Henoch-Schonlein purpura

      2. Polyarteritis nodosa (PAN)

      3. Leukocytoclastic vasculitis

      4. Rheumatic vasculitides

      5. Cryoglubulinemia

    2. Infection

      1. Meningococcemia

      2. Rickettsial diseases

      3. Hepatitis C

      4. HIV

    3. Medications

      1. Propylthiouracil (PTU)

      2. Hydralazine

      3. NSAIDs

      4. Penicillin

      5. Anti-TNF factors

      6. Corticosteroids

    4. Congenital

      1. Hereditary hemorrhagic telangiectasia

      2. Ehlers-Danlos syndrome

    5. Trauma

    6. Other

      1. Vitamin C deficiency

      2. Amyloidosis

  3. Coagulation factor deficiencies

    1. Congenital

      1. Hemophilia

      2. von Willebrand disease

    2. Acquired

B. Describe a diagnostic approach/method to the patient with this problem.


1. Historical information important in the diagnosis of this problem.

  • Onset and duration

  • Exposures to medications, drugs or chemicals

  • Antecedent illnesses

  • Associated symptoms

    • ◦ Abdominal pain

    • ◦ Hematochezia

    • ◦ Arthralgias

    • ◦ Fever

    • ◦ Confusion

    • ◦ Mucosal bleeding

    • ◦ Hemarthrosis

  • History of connective tissue disease or malignancy

  • Family history

2. Physical Examination maneuvers that are likely to be useful in diagnosing the cause of this problem.

  • Blanching can be tested by placing a glass slide over the area and pushing down

  • Location

    • ◦ lower extremities suggests Henoch-Schonlein purpura

    • ◦ palms and soles suggests rickettsial infection

  • Palpable purpura suggest vasculitis (but is not pathognomonic)

  • Bleeding around hair follices and "corkscrew hairs" suggest vitamin C deficiency

  • Skin hyperelasticity and joint hypermobility suggest Ehlers-Danlos syndrome

  • Lymphadenopathy

  • Splenomegaly

  • Stigmata of cirrhosis

3. Laboratory, radiographic and other tests that are likely to be useful in diagnosing the cause of this problem.

Initial laboratory testing should include:

  • CBC with peripheral smear

  • PT and PTT

  • Urinalysis with microscopy

A skin biopsy can be obtained depending on the clinical circumstance.

C. Criteria for Diagnosing Each Diagnosis in the Method Above.


D. Over-utilized or “wasted” diagnostic tests associated with the evaluation of this problem.


III. Management while the Diagnostic Process is Proceeding.

A. Management of Clinical Problem Purpura/Petechiae.

Management depends on the etiology of the purpura but should begin with removal of the offending agent if one is identified.

B. Common Pitfalls and Side-Effects of Management of this Clinical Problem.


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