What should be done for a child undergoing chemotherapy (chemo) who develops bruising on the legs?

Management of Bruising in Children Receiving Chemotherapy

For a child undergoing chemotherapy who develops bruising on the legs, immediately check the platelet count and assess for thrombocytopenia-related bleeding complications, as this represents a potentially life-threatening side effect requiring urgent medical evaluation.

Immediate Assessment Required

Check Complete Blood Count with Platelets

• Thrombocytopenia is the most likely cause of bruising in children receiving chemotherapy and requires immediate laboratory confirmation to guide management decisions.
• Chemotherapy-induced myelosuppression commonly causes platelet counts to drop, increasing bleeding risk.
• The location (legs/upper leg area) and context (active chemotherapy) make this a medical emergency until proven otherwise.

Evaluate Bleeding Severity

• Assess whether bruising is isolated or accompanied by other bleeding manifestations (petechiae, mucosal bleeding, hematuria).
• Only 41% of patients appropriately recognize unusual bleeding or bruising as requiring immediate medical attention, highlighting the critical need for provider vigilance 1.
• Document the extent, pattern, and timing of bruising relative to chemotherapy administration.

Management Based on Platelet Count

Severe Thrombocytopenia (Platelets <20 × 10⁹/L)

• Hold all anticoagulation including prophylactic low-molecular-weight heparin (LMWH) if the child is receiving thromboprophylaxis 2.
• Administer platelet transfusions to maintain counts >20 × 10⁹/L for prophylaxis or >50 × 10⁹/L if active bleeding is present.
• Avoid intramuscular injections and invasive procedures.

Moderate Thrombocytopenia (Platelets 20-50 × 10⁹/L)

• Prophylactic LMWH dosing may be continued at platelet counts >20 × 10⁹/L if the child is on thromboprophylaxis for other indications 2.
• Therapeutic anticoagulation should be modified, with full dosing reserved for platelets >50 × 10⁹/L with transfusion support as necessary 2.
• Monitor closely for progression of bleeding.

Normal or Near-Normal Platelet Count

• If platelets are adequate, investigate alternative causes:
  • Coagulation factor deficiencies (PT/PTT, fibrinogen)
  • Inherited bleeding disorders (von Willebrand disease, hemophilia)
  • Drug-induced coagulopathy (asparaginase can cause multiple hemostatic abnormalities)
  • Vitamin K deficiency
• Bruising may indicate underlying hemostatic abnormalities that require specific investigation beyond routine platelet assessment 3.

Chemotherapy-Specific Considerations

Asparaginase-Containing Regimens

• Asparaginase causes complex hemostatic changes including both bleeding and thrombotic complications.
• Consider higher prophylactic LMWH dosing or anti-Xa monitoring in patients receiving asparaginase due to altered pharmacokinetics 2.
• Monitor fibrinogen levels, as asparaginase commonly causes hypofibrinogenemia.

Other Myelosuppressive Agents

• Ifosfamide can cause additional complications including renal dysfunction and Fanconi syndrome, which may contribute to bleeding risk through multiple mechanisms 4.
• Timing of nadir (typically 7-14 days post-chemotherapy) should guide monitoring frequency.

Critical Pitfalls to Avoid

Do Not Dismiss as "Normal Chemotherapy Side Effect"

• While thrombocytopenia is expected with chemotherapy, visible bruising always requires objective assessment to quantify severity and guide intervention.
• Failure to recognize severe thrombocytopenia can lead to life-threatening hemorrhage including intracranial bleeding.

Do Not Assume Abuse Without Medical Workup

• The provided guidelines on skeletal surveys 2 address bruising in the context of suspected non-accidental injury in young children.
• These abuse-focused guidelines are NOT applicable to children with known chemotherapy exposure, as the oncologic context provides a clear medical explanation.
• Complete hematologic evaluation must precede any consideration of alternative diagnoses.

Do Not Delay Platelet Transfusion

• Prophylactic transfusion thresholds exist to prevent progression from minor bruising to major hemorrhage.
• Waiting for "more serious" bleeding before transfusing increases morbidity and mortality risk.

Patient and Family Education

• Educate families that unusual bleeding or bruising requires immediate medical attention, as many patients underestimate the urgency of this symptom 1.
• Provide clear instructions on when to seek emergency care versus routine oncology follow-up.
• Emphasize that approximately 40% of children receiving aggressive chemotherapy will experience significant myelosuppression requiring supportive interventions 5.