Back when the fever is gone and they feel well enough for class: CDC guidance does not require waiting for every blister to heal, though many schools and daycares set stricter policies.
HFMD is most contagious in the first week, but virus lingers in saliva and stool for weeks, so exclusion can never be perfect and hygiene does the real work: handwashing after diaper changes and bathroom visits, no shared cups or utensils, disinfected surfaces. The illness runs 7 to 10 days; mouth sores are the rough part, eased with cold drinks, ice pops, and acetaminophen or ibuprofen, while acidic foods sting. The watch-out is dehydration because drinking hurts: few wet diapers, no tears, or refusing fluids entirely earns a call to the doctor. Check your daycare or school's specific rule before returning; their policy, not the CDC's, is what the front desk enforces. Adults catch it too, usually milder.
What to do
Common questions
When can my kid go back to school after hand, foot, and mouth?
Hand, foot, and mouth disease (HFMD) is most contagious during the first week of illness, but the virus can linger in saliva and stool for weeks after symptoms clear, which is why perfect exclusion is impossible. The practical return rule from CDC guidance: children can go back when the fever is gone, they feel well enough to participate, and there is no uncontrolled drooling with mouth sores or weeping blisters; there is no need to wait until every spot has healed. The override that matters most: daycare centers and schools set their own policies, and many daycares are stricter than the CDC, so check before showing up. The hygiene reality: HFMD spreads through droplets, blister fluid, and stool (diaper changes are a major route), so handwashing after bathroom and diaper changes is the real spread-breaker for the weeks of viral shedding that follow. Expect the illness itself to run 7 to 10 days, with mouth sores the most miserable part: cold drinks, ice pops, and acetaminophen or ibuprofen help, and skip acidic foods. Watch for dehydration, since painful mouth sores stop kids from drinking: few wet diapers or very little urine, no tears, or refusal to drink at all means call the doctor. Adults can catch it too, usually milder.