Sepsis Can Cause a Red Line on Your Skin—Here’s What You Need to Know

A mom took to Facebook to warn parents about a mark on her son’s arm that signaled a potentially fatal disease.

The mother, Alexandra Ruddy, posted a photo of that mark that left her with an uneasy feeling about her son’s health. This gut instinct led her to take her son to the doctor’s office immediately. And it’s a good thing she did: Her eight-year-old son had sepsis.

“Yesterday on our way to the beach he showed me his hand. I wasn’t happy as I noticed red tracking down his vein. I then checked his elbow—the same,” Ruddy wrote on Facebook earlier this month. She admitted that she felt “a bit silly” seeking medical help after noticing the red lines, but her instincts proved right. “[The doctor] commended me on recognising it and getting [to the doctor] ASAP. This is blood poisoning/sepsis. It isn’t something you can ‘leave’ until Monday when the doctors are back in the office.”

Sepsis is a potentially fatal condition that’s caused by a reaction the body has to an infection. Ruddy mentioned that her son had recently taken a fall that resulted in open wounds. She wrote that the wounds didn’t look infected when she noticed the red mark on his arm, highlighting the fact that sepsis can occur with little warning.

“Sepsis is the most serious form of any infection,” Frank Esper, MD, pediatric infectious disease specialist at Cleveland Clinic, tells Health. “Sepsis is when you have an infection so bad it is disseminating across the body—kidneys shutting down, liver shutting down, heart’s in trouble.” This is why seeking medical care quickly is of the upmost importance once symptoms of sepsis appear. These include mental decline, a fever, and fatigue.

RELATED: This Woman Almost Died From Sepsis at Age 39—and it Taught Her an Important Lesson

Dr. Esper talked about why this mark might pop up if you have an infection—and what to do if you notice one on yourself or a friend or family member. Marks like these can show up if an infection travels through one’s lymph nodes to other parts of the body, he explains. “It’s very concerning. You need to be on antibiotics immediately,” Dr. Esper says, adding that his team sees thesemarks often.

Ruddy wrote that her son’s health has improved since he started taking antibiotics to treat his infection. But she cautions other parents not to wait if they notice a mark like his on their child. “If you spot this red line running from a wound along the vein, get yourself/your child seen straight away,” she wrote.

Dr. Esper says there’s a simple way to keep track of whether or not redness around a wound is spreading, which could signal infection. “Take a pen and mark around the site. Draw a border around the redness,” he says. “Does the redness go beyond that mark [the next day]? If you’re on antibiotics and the redness goes beyond those markings, we’re on the wrong antibiotics or we need something more powerful.”

RELATED: This Woman Has Had Sepsis 5 Times—and Is at Constant Risk of Getting It Again