What is the appropriate initial assessment and work‑up for an 18‑year‑old new patient presenting with easy bruising?

Initial Assessment of Easy Bruising in an 18-Year-Old

Begin with a focused bleeding history to identify symptoms suggesting a true bleeding disorder, then proceed with targeted laboratory screening including CBC with platelet count, PT, aPTT, and peripheral blood smear. 1, 2, 3

Focused Clinical History

Bleeding Symptoms Assessment

• Ask specifically about: significant bleeding after surgery or dental procedures, prolonged epistaxis requiring medical intervention, menorrhagia (if female), joint hemorrhages, or bleeding from minor trauma 1, 2, 4
• Document whether bruises appear spontaneously or only after identifiable trauma 2
• Assess bruise location—bruising on soft tissue areas (thighs, upper arms, trunk) is more concerning than bruising over bony prominences from normal activity 5, 4

Medication and Supplement Review

• Document all medications including NSAIDs, anticoagulants, antiplatelets, corticosteroids, and herbal/alternative therapies, as these affect both bleeding tendency and coagulation test interpretation 1, 2, 4

Family History

• Ask about specific bleeding disorders in relatives (von Willebrand disease, hemophilia, platelet disorders) and ethnicity associated with higher rates of certain bleeding disorders 2, 4

Physical Examination Findings

• Look for signs of systemic illness: joint hypermobility or skin hyperextensibility (Ehlers-Danlos syndrome), petechiae, hepatosplenomegaly, or lymphadenopathy 2, 6
• Mucocutaneous bleeding patterns suggest platelet dysfunction, while hemarthroses or deep hematomas suggest coagulopathy 7

Initial Laboratory Testing

Order the following screening panel: 1, 2, 4, 3

• Complete blood count (CBC) with platelet count to evaluate for thrombocytopenia 1, 2
• Peripheral blood smear to assess platelet morphology and identify structural abnormalities 1
• Prothrombin time (PT) and activated partial thromboplastin time (aPTT) to detect most factor deficiencies 1, 2, 3
• Fibrinogen level if PT or aPTT are abnormal 1, 2

Critical Testing Limitations to Recognize

PT and aPTT do NOT reliably detect von Willebrand disease, Factor XIII deficiency, or platelet function disorders—the most common causes of easy bruising with normal screening tests. 1, 2, 4 If clinical suspicion remains high despite normal PT/aPTT, specific testing for these conditions is necessary.

Interpretation Algorithm

If PT and aPTT are Normal

• High likelihood of von Willebrand disease or platelet function disorder 1
• Proceed with VWD-specific testing: VWF antigen, VWF ristocetin cofactor activity, and Factor VIII coagulant activity 1
• Consider platelet function testing if VWD testing is negative 1, 2

If aPTT is Prolonged with Normal PT

• Indicates intrinsic pathway deficit 3, 7
• Perform mixing study to distinguish factor deficiency from inhibitor 7
• Consider hemophilia (Factor VIII or IX deficiency) or Factor XI deficiency 1

If PT is Prolonged with Normal aPTT

• Consider vitamin K deficiency or Factor VII deficiency 7
• Vitamin K challenge may be diagnostic 7

If Both PT and aPTT are Prolonged

• Evaluate for liver disease, vitamin K deficiency, or disseminated intravascular coagulation (DIC) 1, 2

When to Refer to Hematology

Refer when: 1, 2, 4

• Initial laboratory evaluation indicates a bleeding disorder
• High clinical suspicion persists despite normal screening tests
• Specialized testing is needed (platelet aggregation studies, VWD multimer analysis, Factor XIII assay)
• Complex cases require expert interpretation

Common Pitfalls to Avoid

• Do not assume normal platelet count excludes platelet disorders—qualitative platelet defects can occur with normal or even elevated platelet counts 1
• Avoid extensive testing without clinical indication—the extreme rarity of some bleeding disorders makes universal screening unreasonable in patients with typical bruising patterns and no bleeding symptoms 2, 4
• Ensure proper specimen handling—coagulation tests are very sensitive to specimen handling, and inappropriate collection commonly leads to false-positive results 1
• Do not overlook medication effects—certain drugs affect both bleeding tendency and test interpretation 1, 2