Can hand, foot, and mouth disease (HFMD) lesions present on other parts of the body beyond the hands, feet, and mouth?

Hand, Foot, and Mouth Disease Lesions Beyond the Classic Locations

Yes, hand, foot, and mouth disease (HFMD) lesions can definitely appear on other parts of the body beyond the hands, feet, and mouth, including the buttocks, legs, arms, trunk, and perioral areas. 1, 2

Distribution of HFMD Lesions

HFMD typically presents with the classic triad of lesions on:

• Hands (palms)
• Feet (soles)
• Oral mucosa

However, clinical studies have documented a spectrum of presentations from classical to generalized exanthema:

• Widespread involvement: 41.5% of children with confirmed HFMD have 5 or more anatomical sites involved 2
• Additional common sites:
  • Buttocks (particularly common)
  • Legs
  • Arms
  • Trunk
  • Perioral region (especially with coxsackievirus A6) 2

Factors Affecting Distribution

The distribution of lesions can be influenced by:

1. Viral serotype:

   • Coxsackievirus A6 (CV-A6) is particularly associated with perioral rash and more widespread exanthema 2
   • Coxsackievirus A16 (CV-A16) can also cause generalized vesicular eruptions 2

2. Underlying skin conditions:

   • Children with atopic dermatitis may develop "eczema coxsackium," where the virus preferentially affects areas of eczematous skin 3
   • This pattern can mimic herpetic superinfection and requires careful differentiation

Clinical Presentation Beyond Classic Sites

The appearance of lesions varies by location:

• Classic sites (hands, feet, mouth): Vesicular lesions that may evolve into erosions or ulcerations
• Buttocks: Often vesicular lesions that can be more numerous than on hands/feet
• Trunk and limbs: May present as maculopapular or vesicular eruptions
• Perioral area: Vesicular or erosive lesions around the mouth, particularly with CV-A6 infections 2

Special Considerations

1. Atypical presentations:

   • Generalized vesicular exanthema can occur with both CV-A6 and CV-A16 infections 2
   • These widespread presentations may be misdiagnosed as other viral exanthems

2. Delayed manifestations:

   • Nail changes (shedding or dystrophy) may appear weeks after the initial infection 1, 3
   • These can include Beau's lines or complete nail shedding

3. Severity indicators:

   • Extensive cutaneous involvement does not necessarily correlate with increased risk of complications
   • Neurological complications are more associated with enterovirus 71 regardless of rash distribution 4

Diagnostic Approach

When evaluating a patient with suspected HFMD:

1. Examine all skin surfaces, not just hands, feet, and mouth
2. Pay special attention to the buttocks, which are commonly affected
3. In children with atopic dermatitis, carefully assess eczematous areas for viral involvement
4. Consider HFMD in the differential diagnosis of any vesicular rash, even when classic sites are spared

The diagnosis of HFMD remains primarily clinical, with widespread exanthema being a recognized variant rather than an atypical presentation.