A few years ago, in my mid-30s, I broke out in a rash that stretched horizontally across my torso, from the middle of my back to the front of my ribcage. At first, I thought it might be from wearing my bra too many days in a row without washing it. Weirdly, I also felt like I was coming down with the flu. Overnight, the rash got more prominent, and my flu-like symptoms got worse, so I went to see my primary care doctor right away.

In her office, I lifted my shirt and turned. Immediately and definitively, she told me I had shingles. What? “I thought only senior citizens got shingles,” I said.

Like many adults on the south side of middle age, I had barely even heard of the disease at the time of my diagnosis. Shingles results in a painful red rash that breaks out in a band adjacent to the spine; it can also cause an upset stomach, fever and chills. A few telltale signs make it easily recognizable: The rash extends from the spine but does not cross the midline of the body, and it will affect one side of your torso but not the other.

About 1 in 3 people will get sick with shingles in their lifetime. It’s caused by the same virus behind chickenpox, varicella zoster. The virus remains dormant in the body following a case of chickenpox, prompting a shingles outbreak later in life.

If you’ve never had chickenpox, exposure to someone with shingles can give you a case of chickenpox.

For years, the rate of shingles in all age groups has been on the rise, though experts don’t know why. While shingles is most common among adults older than 50, my doctor explained, she’d been seeing more young people with the illness. After writing me a prescription for the strong antiviral medication that made me better within the week, my doctor asked me if I was under any unusual stress.

In fact, I was. In addition to stressful family events, I was under pressure at work. I was also managing the physical strain of training for a half-marathon. Stress can interfere with your immune system, so it’s one of the things that makes contracting a case of shingles more likely at any age. Some forms of cancers, HIV and certain medications can depress the immune system too, increasing the risk of shingles.

“The youngest patient I’ve had with shingles was 8 years old, and I think stress played a role,” says Dr. Erica Swegler, a family doctor in Austin, Texas. The boy was feeling the pressure of looming standardized testing at school. “He was so worried about the tests,” she says, “that he broke out in shingles.”

While the vast majority of shingles patients are still older adults, the number of cases in patients under 50 is rising. One problem with younger adults and shingles is that they don’t know which symptoms to look out for, primarily because conventional wisdom says they aren’t vulnerable to the disease. As a result, they might delay making a doctor’s appointment, a decision that Swegler says can result in months or even years of pain.

“With prompt treatment, we can mitigate how severe the pain will get and how long it will last,” Swegler says. “If you get treated within 48 to 72 hours of the rash breaking out, you will end up with a milder case of the disease, and you can get better within the week.”

That’s what happened to me, but my sister Jill, 39, who endured a case of shingles earlier this year, wasn’t so lucky. “I waited maybe three weeks or a month before I saw the doctor,” she told me. Even after she was diagnosed and treated, she had two months of pain so intense she had to lie down on the floor of her office a couple times a day. Ten months after the rash first appeared, she still has frequent pain that she describes as merely troublesome. Long-term pain from shingles is called post-herpetic neuralgia.

“Some people have ongoing sensitivity that makes things painful that shouldn’t be, like wearing clothes,” according to Swegler.

The first vaccine to protect against shingles came out in 2006. This vaccine was an attenuated vaccine, meaning that it contains a harmless, much less potent version of the virus, one that doesn’t make you sick but will enhance your defenses against the disease. “That vaccine, averaged across all age groups, was only about 50 percent effective,” Swegler says.

Last fall, a new vaccine called Shingrix, which doesn’t contain the virus, became available. Vaccination with Shingrix is 90 percent effective at preventing the disease and requires two shots anywhere from two to six months apart. Due to its popularity, there’s a shortage of the drug. Swegler says there’s currently a wait list for the new vaccine at her practice.

The Centers for Disease Control and Prevention recommends the vaccine for all healthy adults older than 50. If you’re under 50 and concerned about getting shingles, you can still ask your doctor about getting Shingrix. Because it won’t be covered by your insurance, it will cost roughly $400 — and you’ll probably need to wait until more of the vaccine becomes available.

According to Swegler, 1 in 5 people who get shingles will get it a second time. Like anyone who has lived through the burning pain and unsightly rash that comes with the disease, I do not want to be one of them. So I’ve considered talking to my own doctor about getting the vaccine when it becomes available, despite the staggering price tag. Swegler told me that because I’ve had shingles in the last few years, I can expect to have more resistance to the virus than I otherwise might for at least a few more years. In the meantime, I’m taking stress management seriously.

A smart strategy for those under 50 who want to avoid the long-term nerve pain that often accompanies shingles is to know the symptoms of the virus and see your primary care doctor immediately if you spot them. In other words, if an unexplained band-like rash breaks out next to your spine, and appears on only one side of your body, don’t wait a few months (or even a few weeks) to get it checked out.

Ready to book a doctor’s appointment? Visit Zocdoc.