13. Examination and differential diagnosis of petechiae, purpurae, and suffusions.

Page created on February 14, 2022. Not updated since.

Examination of bleedings into skin

Bleeding into the skin or mucosa is typical for disorders of the platelets or blood vessels, whereas bleeding disorders mostly cause bleeding into soft tissue, muscles, and joints. Petechiae are pinpoint areas (<3 mm) of bleeding, purpura are larger (3 – 10 mm), and ecchymoses are the largest (>10 mm, commonly called bruises). Unlike other erythematous skin lesions, bleedings into the skin do not blanch when pressure is applied to the skin. This is best visualised by pressing glass against the lesion.

Life-threatening conditions, like leukaemia, severe trauma, meningococcal sepsis, DIC, and HUS should be ruled out first. Laboratory examination of CBC, prothrombin time (PT), INR, and aPTT are essential to determine the etiology of the bleeding diathesis. PT, INR, and aPTT are prolonged in case of liver disease, anticoagulant drugs, DIC. aPTT is also prolonged in case of clotting factor deficiency.

Has there previously been excessive bleeding after surgical procedures, trauma, or dental extraction? What’s the distribution of purpura? Is there family history? Has there been any recent illness? Is there any use of hepatotoxic or platelet-affecting drugs? Are there bruises in a pattern which looks like a belt or handprint?

Differential diagnosis of petechiae, purpura, and ecchymoses

Etiology Typical features
Infections (viral, pharyngitis, etc.) Symptoms of infection
Immune thrombocytopaenia Sudden onset, preceded by viral infection
Acute leukaemia Anaemia, lethargy, infections, organomegaly
Meningococcal sepsis Signs of sepsis, meningitis, ill-appearing
Henoch-Schönlein purpura Purpuric rash on butt and extensor surfaces, spares the trunk. Arthritis, abdominal pain
Trauma Incomplete or avoidant history from family, child in pain
Haemolytic uraemic syndrome (HUS) Follows a GI or URTI infection. Acute renal failure, anaemia, schistocytes on blood smear
DIC Bleeding from venepuncture sites, widespread bleeding and thrombosis
Neonatal alloimmune thrombocytopaenia Neonate with no other clinical features
Liver failure Jaundice, hepatomegaly

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