Hello dear, Thank you for your contact to health care magic. I read and understand your concern. I am Dr Arun Tank answering your concern. No, please do not allow them to swim. This causes threat to the other child swimming nearby. I also suggest you to take the prophylactic antibiotics to prevent the secondary bacterial infection to your child. HF&M disease is very benign at a time. It can be cured as such. But in some cases it can be complicated. If you found any convulsion or other issues then you can immediately visit the hospital. This are serious issues and can be dealt properly. To treat this infection at earliest please maintian good hygiene take the antibiotics to prevent secondary infection. Keep him isolated. I will be happy to answer your further concern on bit.ly/DrArun. Thank you, Dr Arun Tank Infectious diseases specialist, HCM.