Can hand, foot, and mouth disease cause thrombocytopenia (low platelet count)?

Hand, Foot, and Mouth Disease and Thrombocytopenia

Hand, foot, and mouth disease (HFMD) is not typically associated with thrombocytopenia as a common complication, and there is insufficient evidence in the medical literature to establish a direct causal relationship between HFMD and low platelet counts.

Understanding Hand, Foot, and Mouth Disease

Hand, foot, and mouth disease is a common viral illness caused by human enteroviruses and coxsackieviruses that primarily affects children under 10 years of age. It is characterized by:

• Low-grade fever
• Maculopapular or papulovesicular rash on hands and feet
• Painful oral ulcerations
• Self-limiting course with lesions resolving in 7-10 days 1

Thrombocytopenia: Causes and Mechanisms

Thrombocytopenia (platelet count <150,000/μL) can occur through several mechanisms:

1. Decreased platelet production
2. Increased platelet destruction
3. Splenic sequestration
4. Dilution or clumping 2

While viral infections can cause thrombocytopenia, the evidence specifically linking HFMD to thrombocytopenia is limited. When evaluating a patient with HFMD and thrombocytopenia, consider other more established causes:

Infection-Related Thrombocytopenia

Certain infections are well-documented causes of thrombocytopenia:

• Dengue
• Malaria
• Scrub typhus
• Rickettsial infections
• Meningococcal infections
• Leptospirosis
• Various viral infections 3

Infections can decrease platelet counts through:

• Effects on platelet production
• Decreased platelet survival
• Development of disseminated intravascular coagulation (DIC)
• Immune-mediated mechanisms 3

Clinical Assessment of Thrombocytopenia

When evaluating thrombocytopenia in a patient with HFMD, consider:

Severity Assessment

• >50,000/μL: Generally asymptomatic
• 20,000-50,000/μL: Risk of mild bleeding (petechiae, purpura, ecchymosis)
• <10,000/μL: High risk of serious bleeding 2

Diagnostic Approach

1. Exclude pseudothrombocytopenia by collecting blood in a tube containing heparin or sodium citrate and repeating the platelet count
2. Determine if acute or chronic by reviewing previous platelet counts
3. Evaluate for other cytopenias with complete blood count
4. Examine peripheral blood smear for platelet size and morphology 2

Management Considerations

If thrombocytopenia is confirmed in a patient with HFMD:

1. Supportive care is the mainstay of treatment for HFMD (hydration and pain relief with acetaminophen or ibuprofen) 1

2. For thrombocytopenia management:

   • Treat the underlying cause when identified
   • Consider platelet transfusion for:
     • Active hemorrhage
     • Platelet counts <10,000/μL
     • Before invasive procedures when counts are inadequate 2

3. Activity restrictions to avoid trauma-associated bleeding if platelet count <50,000/μL 2

Important Considerations

• While HFMD itself is not typically associated with thrombocytopenia, the presence of low platelets should prompt evaluation for other concurrent conditions or complications
• Certain viral infections can trigger immune thrombocytopenia as a secondary phenomenon
• In rare cases, HFMD can have neurologic complications, but thrombocytopenia is not listed among the common complications 1

If a patient presents with both HFMD and thrombocytopenia, consider alternative or additional diagnoses that could explain the low platelet count, as the thrombocytopenia is more likely due to another cause rather than being directly caused by the HFMD virus.