When is hand, foot, and mouth (HFAM) disease contagious?

When is Hand, Foot, and Mouth Disease Contagious?

Hand, foot, and mouth disease (HFMD) is contagious from 3-10 days before symptoms appear until all blisters have dried and crusted over, typically 7-10 days after the onset of symptoms.

Contagious Period Timeline

HFMD follows a specific contagious timeline:

• Incubation period: 3-10 days after exposure before symptoms appear 1
• Initial symptoms: Fever and sore throat are typically the first symptoms 1
• Most contagious period: During the first week of illness, particularly when fever is present and blisters are forming
• End of contagious period: When all blisters have dried and crusted over, typically 7-10 days after symptom onset

Transmission Methods

HFMD spreads through multiple routes:

• Direct contact with saliva, nasal secretions, fluid from blisters, or stool of infected persons 2
• Respiratory droplets from coughing and sneezing 2
• Fecal-oral transmission through contaminated hands, surfaces, or objects 2
• Close personal contact such as hugging, kissing, or sharing utensils 2

Clinical Presentation

Recognizing HFMD is important for controlling spread:

• Low-grade fever (typically first symptom)
• Sore throat and painful oral ulcerations
• Maculopapular or papulovesicular rash on hands, feet, and sometimes buttocks 2
• Oral lesions that can make eating and drinking painful
• Nail changes may occur weeks after initial infection (particularly with coxsackievirus A6) 3

Prevention Measures

To prevent transmission during the contagious period:

• Handwashing is the most effective prevention method, especially after changing diapers, using the toilet, or contact with lesions 2
• Disinfect contaminated surfaces and fomites regularly, especially in childcare settings 2
• Avoid close contact with infected individuals
• Exclude infected children from school or daycare until fever resolves and mouth sores have healed
• Avoid sharing utensils, cups, towels and other personal items

Special Considerations

• Adults can also be infected and transmit the virus, though symptoms are often milder 1
• Multiple viral strains can cause HFMD, including coxsackieviruses A6, A10, A16, and enterovirus 71 1, 4
• Enterovirus 71 and Coxsackievirus A6 strains can cause more severe disease with higher risk of complications 5, 4
• Asymptomatic carriers can still spread the virus 3

Return to School/Childcare Guidelines

Children with HFMD should remain home from school or childcare until:

• Fever has resolved without fever-reducing medications
• Mouth sores have healed enough to allow normal eating and drinking
• Blisters have dried and crusted over
• Generally, this means staying home for 7-10 days from symptom onset

Common Pitfalls in Managing HFMD Transmission

• Assuming contagion ends when fever resolves: Individuals remain contagious until all blisters have crusted over
• Returning to school/daycare too early: This can lead to outbreaks in these settings
• Inadequate hand hygiene: The virus can persist on hands and surfaces for days
• Focusing only on visible symptoms: Asymptomatic carriers can still transmit the virus
• Overlooking fomite transmission: Toys and surfaces can harbor the virus

Remember that HFMD is typically self-limiting with symptoms resolving within 7-10 days, but appropriate precautions during the entire contagious period are essential to prevent outbreaks, particularly in childcare settings and schools.