Can hand foot mouth disease be transmitted through blisters?

Hand-Foot-Mouth Disease Transmission Through Blisters

Yes, hand-foot-mouth disease (HFMD) can be transmitted through direct contact with blister fluid, though this represents only one of multiple transmission routes for this highly contagious viral illness. 1

Primary Transmission Routes

HFMD spreads through three main pathways 1:

• Fecal-oral transmission - the predominant route in most cases
• Oral-oral transmission - through saliva and oral secretions
• Respiratory droplet contact - through coughing and sneezing
• Direct contact with blister fluid - vesicular fluid contains infectious viral particles

Blister-Specific Transmission Mechanisms

Direct contact with the vesicular lesions on hands, feet, or oral mucosa can transmit the causative enteroviruses (coxsackieviruses and enteroviruses) to susceptible individuals. 1, 2 The fluid within these blisters contains high concentrations of viral particles capable of initiating infection in others.

The principles of contact transmission apply here, as established in infection control guidelines 3:

• Contaminated hands are the predominant mode of transmission after touching intact or broken skin lesions 3
• Moist skin transfers organisms more efficiently than dry skin - a critical consideration given the vesicular nature of HFMD lesions 3
• Indirect contact transmission occurs when viral particles from blisters contaminate fomites (toys, surfaces, door handles) which then transfer to susceptible hosts 3

Critical Infection Control Measures

Hand hygiene with soap and water or alcohol-based hand rub is the single most important prevention measure to interrupt transmission from blister contact 4, 1. This is particularly crucial because:

• Healthcare workers and caregivers can contaminate their hands by touching lesions during routine care activities 3
• The virus can survive on environmental surfaces and be transmitted indirectly 3
• Handwashing must occur before and after contact with each patient or their immediate environment 3

Additional Prevention Strategies

Beyond hand hygiene, preventing blister-mediated transmission requires 1:

• Disinfecting potentially contaminated surfaces and fomites - essential given the vesicular nature of the disease
• Avoiding direct contact with lesions during the acute phase when vesicles are present
• Contact precautions similar to those used for respiratory syncytial virus, given the contact transmission potential 4

Clinical Context and Timing

The vesicular rash typically appears as maculopapular or papulovesicular lesions on hands and soles along with painful oral ulcerations 1. These lesions usually resolve in 7-10 days 1, during which time they remain potentially infectious through direct contact.

The contagious period extends beyond visible lesions - patients can shed virus in stool for weeks after clinical recovery, making fecal-oral transmission a persistent concern even after blisters heal 1, 2.

Common Pitfall to Avoid

Do not assume that once blisters crust over, transmission risk is eliminated. Unlike varicella where crusted lesions are non-infectious, HFMD patients remain contagious through fecal shedding long after skin lesions resolve 1. Focus infection control efforts on hand hygiene and environmental disinfection throughout the illness and recovery period, not just during the vesicular phase.