What causes spontaneous bruising?

Causes of Spontaneous Bruising

Spontaneous bruising can be caused by bleeding disorders, medical conditions affecting blood vessels, vitamin deficiencies, medications, or physical abuse, with the most common causes being coagulation factor deficiencies, platelet disorders, and vascular abnormalities. 1

Bleeding Disorders

Coagulation Factor Deficiencies

• Von Willebrand disease (VWD) - the most common inherited bleeding disorder with a prevalence of approximately 1 in 1000 people, presenting with mucocutaneous bleeding and easy bruising 1
• Hemophilia (Factor VIII or IX deficiency) - can cause significant bruising and bleeding even with mild deficiencies, particularly concerning in males 1
• Other factor deficiencies (II, V, VII, X, XI) - rarer causes of spontaneous bruising but should be considered in specific ethnic populations (e.g., Factor XI deficiency in Ashkenazi Jewish population) 1
• Factor XIII deficiency - not detected by standard PT/aPTT screening tests but can cause significant bruising 1

Platelet Disorders

• Immune thrombocytopenia (ITP) - a transient, often self-resolving bleeding disorder characterized by low platelet count 1
• Platelet function disorders - can present with bruising and mucocutaneous bleeding; diagnosis requires specialized testing such as platelet aggregation studies 1
• Bernard Soulier syndrome and Glanzmann thrombasthenia - rare but severe platelet function disorders 1

Vitamin Deficiencies

Vitamin K Deficiency

• Particularly important in infants who haven't received vitamin K prophylaxis at birth 1
• Presents with prolonged PT and possibly aPTT 1
• Can cause generalized ecchymoses, bleeding from mucosal surfaces, and intracranial hemorrhage 2

Vitamin C Deficiency (Scurvy)

• Characterized by mucocutaneous petechiae, poor wound healing, ecchymosis, and easy bruising 3
• Still occurs in developed countries, especially in individuals with limited access to fruits and vegetables 4

Vascular and Connective Tissue Disorders

Ehlers-Danlos Syndrome (EDS)

• Heterogeneous group of connective tissue disorders with easy bruising due to capillary and perivascular connective tissue fragility 5
• Vascular subtype (caused by collagen type III defect) is particularly associated with extensive bruising and spontaneous arterial rupture 5
• Haematological studies including clotting factors and platelet aggregation are usually normal, but capillary fragility tests may be abnormal 5

Other Vascular Conditions

• Arteriovenous malformations can cause localized bleeding and bruising 1
• Senile purpura - thinning of blood vessels and skin with aging

Other Medical Causes

• Liver disease/cirrhosis - can lead to decreased production of clotting factors and spontaneous bruising 1
• Disseminated intravascular coagulation (DIC) - can cause any type of bruising/bleeding, including intracranial hemorrhage 1
• Malignancies and infiltrative disorders - can cause thrombocytopenia or coagulation abnormalities 1
• Medications - anticoagulants, antiplatelets, NSAIDs, steroids, and some antibiotics can increase bruising tendency 1

Diagnostic Approach

Initial Screening Tests

• Complete blood count with platelet count - to evaluate for thrombocytopenia 1
• Prothrombin time (PT) and activated partial thromboplastin time (aPTT) - detect most factor deficiencies but not VWD or factor XIII deficiency 1
• Fibrinogen concentration and thrombin time - to detect defects of fibrinogen 1

Additional Testing Based on Clinical Suspicion

• Specific factor assays (VIII, IX) - particularly important if mild hemophilia is suspected 1
• Von Willebrand factor testing - if VWD is suspected 1
• Platelet function testing - for suspected platelet disorders 1
• Vitamin levels (K, C) - if deficiency is suspected 1, 3

Special Considerations

In Children

• Pattern and location of bruising must be carefully evaluated to distinguish between bleeding disorders and potential abuse 1
• Bruising in non-mobile infants, especially in unusual locations (buttocks, ears, genitals), raises concern for abuse 1
• Bleeding disorders are generally permanent conditions that do not resolve with change in caregivers 1
• Certain findings may exclude the need for bleeding disorder evaluation:
  • Caregiver's description of trauma sufficiently explains bruising
  • Child or witness provides history of trauma explaining bruising
  • Presence of abusive object or hand-patterned bruising 1

In Adults with Cirrhosis

• Abnormal laboratory tests (INR, APTT, platelet count, fibrinogen) are common but don't necessarily predict spontaneous bleeding 1
• Clinically non-significant bleeding such as bruises or epistaxis is common in patients with cirrhosis 1

By understanding the various causes of spontaneous bruising, clinicians can develop an appropriate diagnostic approach based on patient age, clinical presentation, and associated symptoms to identify potentially serious underlying conditions.