The contagious disease is popping up just before kids are set to go back to school.
Doctors in several states are reporting cases of hand, foot and mouth disease.
It's a painful illness usually seen in kids under the age of 10.
"It’s picked up easily in day care centers, especially,” according to Dr. Trachella Johnson Foy, a family physician for Baptist Health in Jacksonville, Florida.
Now some doctors are warning parents about it.
"Of course, with us getting back to school — the elementary school children are going to be at a high risk,” Foy said.
"It’s usually composed of a fever, rash that can develop in the mouth with blisters or sores on the hands and the foot.”
It generally runs its course in three to five days.
“It’s easily spread, so the way we try to prevent children from passing it to each other is making sure we do good hand-washing,” Foy said.
She also said it's also important to cover your mouth when coughing and sneezing.
One mother said she makes sure her 6-year-old son takes these steps to prevent him from catching it -- or any other illness.
"I make sure he washes his hands, he don’t share drinks and stuff with people. Or like he just don’t need to be trying to cough on people. He knows to cover his mouth all the time,” Tiffani Allen said.
Foy said there’s been an uptick in hand, foot and mouth disease in the United States recently.
"I know that some of my colleagues have reported seeing a few more cases of it," she said.