Jodie Thomas posted a warning on Facebook that soon went viral after her daughter developed sepsis after trying on shoes at a store in the UK without socks.

Thomas wrote last month, “For all parents please put socks on you’re [sic] children while trying new shoes on. I’m guilty not doing it for mine and myself, but this can be the outcome infection spreading throughout the body.”

She also shared several pictures of her daughter, Sienna, in the hospital bed with an infected wound at the base of her pinky toe.

Thomas had taken her daughter to the doctor the day after their shopping trip, “when she started crying in agony.” The doctor then noticed the four-year-old’s infected food and “used a pen to draw a line around where the infection had spread,” reports MetroUK.

The following day, Thomas rushed her daughter back to the hospital when she noticed that the infection spread up her leg. Sienna was also sporting a fever and was “shaking and twitching.”

Doctors quickly diagnosed Sienna with sepsis, which happens when bacteria from an infection enters the bloodstream and can be fatal. Hospital staff thought they would need to operate but they managed to “drain all the pus from her leg and say the antibiotic drip will do the job.” Sienna was sent home a few days later.

After Sienna’s harrowing experience and her mother’s warning, the obvious question is where can we be safe walking barefoot? And will wearing socks really help?

A few medical practitioners help clear up the answers to these burning questions.

Sepsis can occur after an illness but can also develop from an open wound. William Schaffner, MD, an infectious disease specialist at Vanderbilt University Medical Center, thinks that in Sienna’s case, she may have already had an abrasion on her foot as she was trying on shoes.

“That abrasion provided a location for bacteria to enter her body,” says Dr. Schaffner. “About 99% of the time, those wounds will heal without any difficulty. But occasionally, they will cause further problems.”

So where did Sienna’s infection come from?

Surprisingly, Dr. Schaffner says it probably wasn’t from the shoes she was trying out. He said it was likely she was infected by bacteria she was already carrying on her skin.

To make sense of this statement, we need to understand that our bodies carry all types of bacteria. For instance, Group A streptococcus live in our noses, throats, and skin and can be completely harmless. But if they enter through an open wound, serious infections can occur.

In short, while going barefoot can expose you to more bacteria than normal, they’re likely no more dangerous than the bacteria you already do carry. What’s more important is to be careful of anything sharp or abrasive that can cause punctures or abrasions on the skin.

Sienna’s mom is encouraging other parents to “carry a pair of spare socks” when out shopping for shoes with their kids. And while Dr. Schaffner thinks it isn’t likely the infection came from the shoes, he says socks are still a good idea.

“It’s possible that she got this abrasion while trying on shoes,” he says. “If that’s the case, wearing socks likely would have prevented that friction and prevented the abrasion in the first place.”

Grace Torres-Hodges, DPM, a podiatrist in Pensacola, Florida and a spokesperson for the American Podiatric Medical Association, also thinks socks are a good idea when you’re trying out shoes not your own.

“Bacteria can lead to cellulitis, fungus can lead to athlete’s foot or nail infections, and viruses can lead to warts,” she says. “When you see commercials for Clorox or Lysol about what’s living on surfaces, those same germs can absolutely live in shoes.”

Dr. Schaffner says that the biggest lesson one can take away is that anyone is vulnerable to life-threatening infections from any type of wound. “That’s why it’s important to pay close attention, clean the wound with soap and water, and put a bandage on it to protect it from infection or further irritation,” he says.

And if the cut, blister, or insect bite becomes, red, swollen, or discharges pus, see a doctor immediately.

“Obviously, we undertake activities every day that put our feet at risk of abrasions,” Dr. Schaffner says, “from walking on the beach or doing carpentry around the house.” Injuries and abrasions are a natural occurrence, he adds, “so the lesson is to clean them out and watch them carefully.”

Dr. Torres-Hodges adds, “Your skin is the greatest barrier against any kind of infection, which is why we’re so particular about watching for areas where there is rubbing or calluses, or dry skin that could crack and break open.”