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If you’ve ever read the fine print on a box of tampons, you’ve seen the dire warning that they can cause Toxic Shock Syndrome, which is quote “a rare disease that can be fatal.” And that’s true. But toxic shock syndrome, or TSS for short, isn’t limited to tampons.

In fact, in the U. S., a lot of cases have nothing to with menstruation, and almost half of all cases are in males. Which is why everyone should know what it is and what the warning signs are, even though your odds of getting it are really, really low.

The onset of TSS is usually sudden, things like high fever, rash, and low blood pressure all appear seemingly out of the blue. The disease quickly progresses until your skin is literally peeling off and multiple organs fail. And bacteria are to blame.

Almost all cases can be attributed to infections with either Staphylococcus aureus (the infamous “staph”) or Streptococcus pyogenes (better known as “strep”). And that’s because both of them can produce toxins that act as superantigens. Your immune system is constantly on the lookout for foreign substances or other threats, which are collectively referred to as antigens.

These antigens activate the immune system, including B cells, which produce antibodies, and T cells, which directly attack invaders and signal to other cells to ramp up defenses. As the name implies, superantigens trigger your immune system in a big way. Instead of activating 0.01-0.1% of T cells like normal antigens, they set off 5-30% of them.

For those doing the math, that’s 50 to 3,000 times the normal immune response. The immune system gets so out of control that it actually starts damaging your own tissues. If left unchecked, it can end up literally killing you.

Frighteningly, the main two types of bacteria involved in all this aren’t rare. A lot of people have them harmlessly growing on their skin or other parts exposed to the outside world, like their mouths. For example, a study of over 100 healthy preschool children found that a little over 15% were carrying strep and more than 50% were carrying staph.

And even when strep and staph do cause problems, the illnesses are usually pretty minor and treatable with antibiotics. Don’t get me wrong, having strep throat sucks, but the vast majority of the time, it’s not life-threatening. What’s not well understood is why they go from causing mild illnesses to potentially killing you with TSS.

Not all strains have these superantigens, and even those that do don’t produce them all the time. Microbiologists have found that the environment the bacteria are living in can turn the genes for them on or off. And that’s where tampons come in.

About half of staph-related cases are associated with menstruation or tampon use. Tampons are kind of like petri dishes, providing a warm, moist environment for bacteria to grow. Which is why it’s important to change a tampon every 4 to 8 hours.

The longer a tampon is left in, the more time bacteria have to multiply. And other factors may be at play, too. Using a tampon that’s really absorbent can dry out the vagina and cause tiny scratches that allow toxins to enter the bloodstream more easily.

Another hypothesis is that the tampon introduces oxygen into the vagina, which triggers a shift in bacterial gene expression, making it more likely to produce superantigens. And all of this is why, in the early ‘80s when super-absorbent tampons were really popular and people were just leaving them in for days, there were a lot more tampon-related cases. But anything you put inside your body and leave there for a while could do the same thing, hence doctors flipping out over those jade eggs.

Now the other half of staph-related cases come from all sorts of staph infections, including ones that occur after surgery, childbirth, burns, skin lesions, or even the flu. And strep-associated TSS is pretty much a complete mystery. Many cases seem to stem from infected skin lesions.

But in others, the patient doesn’t have an infected cut or scrape, or any other obvious way for the bacteria to have entered their body. And doctors often can’t figure out why the strep started to grow out of control or produce TSS-inducing toxins. So if you’ve ever gotten an infected cut or had strep throat, there was a chance, albeit a small one, of you developing TSS.

Treatment usually involves supportive care like fluids and medications to keep blood flowing around the body, as well as antibiotics to knock out those bacteria. In severe cases, doctors may also give the patient intravenous immunoglobulin or IVIG. This is basically the pooled antibodies from the blood of 1000 or more human donors.

For unknown reasons, some people produce really effective antibodies that neutralize superantigens before things get out of control. And most people develop antibodies against some of the common superantigens by adulthood. So it’s thought that IVIG can help dial back the immune system, although, not every trial has found it significantly improves survival.

All in all, staphylococcus-related TSS has a fatality rate below 5%, but streptococcus-related TSS has a fatality rate of 30-70%. If all this has you super freaked out just stop for a second. Take a deep breath.

Yes, TSS is scary, but the chances that you’ll get it are pretty low. In the US in 2016, there were just 323 identified cases of TSS, about 90% of which were associated with strep bacteria. And they were split almost 50/50 between males and females.

That’s about one case of TSS in every million people. And there are steps you can take to lower your risk. These include using tampons correctly, properly caring for wounds, washing your hands, and alerting your doctor early if you think you might have an infection.

Thank you for watching this episode of SciShow! And thanks as always to our patrons on Patreon. We couldn’t do what we do without them.

If you want to support our team and help us keep making free educational science videos, just go to Patreon.com/SciShow to join our community of patrons. [ ♪ Outro ].