Boy with symptoms hand, foot and mouth disease.

Hand, foot, and mouth disease is one of many infections that causes mouth sores. Health care providers can usually identify mouth sores caused by hand, foot, and mouth disease by considering

  • how old the patient is
  • what symptoms the patient has
  • how the rash and mouth sores look

A health care professional may sometimes collect samples from the patient’s throat or feces (poop), then send them to a laboratory to test for the virus.