A study by John Hopkins researchers have found that children in the US are being targeted by a new virus.
"What we are seeing is a relatively common viral illness called hand-foot-and-mouth disease but with a new twist," says Bernard Cohen, director of pediatric dermatology at Johns Hopkins Children's Center.
"Your child is seemingly in perfect health when he or she goes to bed but wakes up with high fever and bright red blisters all over the body.
Johns Hopkins dermatologists say the disturbing scenario has become quite common in the last few months.
Cohen and colleague Kate Puttgen have seen close to 50 such cases in the last few months.
This figure may be just the tip of the iceberg, said Cohen.
Cohen and Puttgen want to reassure parents that most cases are benign and that nearly all patients recover in seven to 10 days without treatment and without serious complications.
The coxsackie virus strikes infants and children under five years in the summer and autumn months.
Symptoms include fever and malaise and, a day or two later, a non-itchy skin rash with flat or raised red spots on the hands and feet and/or mouth sores.
The new strain, however, behaves somewhat differently from its home grown cousin, Cohen said.
Cohen and Puttgen advise frequent hand washing and good general hygiene.
"If the child has low-grade fever, but is otherwise well, waiting and watching is appropriate," added Cohen.