The infection gets its name from the blistering rash it causes on the hands, feet, and inside the mouth.
It looks scary, but usually goes away in 7 to 10 days.
However, it is highly contagious - kids often pick it up from daycare, pools, and camps.
"Because this is spread by contact, usually from one person's skin to another person's skin, the best thing to do is always make sure you wash your hands," said Dr. Frank Esper.
There's no treatment for the virus, just rest and fluids, but it can cause complications for young babies and anyone with a compromised immune system.
While it usually affects children, adults, seniors and teenagers can also catch it.
In fact, a high school football team in Ohio canceled a training camp a few weeks ago because several players had it.
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