What to Know About Diphtheria

Medically Reviewed by Melinda Ratini, MS, DO on July 07, 2022
6 min read

Diphtheria is a serious, sometimes deadly bacterial infection that forms in the moist inner lining of your nose and throat, and occasionally on the skin.

It can bring on breathing and swallowing problems, and in some cases sores on the skin.

It’s highly contagious. It spreads easily from person to person, either through the air in small droplets or on surfaces.

Diphtheria is rare in developed countries like the United States. That’s because high vaccination rates have almost gotten rid of the disease.

But diphtheria is still a common problem in many countries around the world.

A type of bacteria called Corynebacterium diphtheriae causes it. This bacteria is unique because it makes a toxin that kills your cells. That makes diphtheria deadlier than some other types of bacterial infections.

The bacteria usually spreads through droplets that fly out of your nose or mouth when you sneeze or cough.

Some people also catch diphtheria by touching an infected person’s used hand towels, tissues, or any of their other things around the house that might hold the bacteria.

You could get diphtheria by touching an infected person’s open sore or ulcer, too.

People with diphtheria are highly contagious until 48 hours after they start getting antibiotic treatment.

It’s also possible to get the bacteria from someone who’s infected but doesn’t have any symptoms. Doctors call this person a “carrier.” Carriers can spread the infection to others for up to 4 weeks.

If you catch diphtheria from a carrier, the bacteria can still turn into a serious infection, even though it was spread by someone who felt fine.

In the U.S., you’re only at risk for the disease if you haven’t gotten the diphtheria vaccine.

There are still many countries around the world, though, where diphtheria is common due to low vaccination rates.

Since 2016, outbreaks of the type of diphtheria that affects the nose and throat have happened in:

  • Indonesia
  • Bangladesh
  • Myanmar
  • Vietnam
  • Venezuela
  • Haiti
  • South Africa
  • Yemen

Diphtheria infections of the skin are common in tropical countries.

In poorer places, it may be harder to get health care and vaccines. Also, people live in close quarters and have less access to hygiene, which causes the disease to spread faster.

So, if you haven’t gotten the diphtheria vaccine, be aware that your chances of catching the disease could go up if you travel internationally or have contact with unvaccinated people from developing countries.

When the diphtheria bacteria grows in the moist inner lining of your nose and throat, it begins to make large amounts of a toxin. This toxin kills your cells and creates a thick gray coating – called a pseudomembrane – from dead cells, bacteria, waste products, and proteins.

This thick substance can coat your nasal tissues, tonsils, voice box, and the rest of your throat. It’s the most distinct symptom of diphtheria, and it can make it hard for you to breathe and swallow.

From your throat, the toxin can get into your bloodstream and cause lots of damage to other tissues and organs throughout your body.

Possible symptoms from diphtheria include:

A second type of diphtheria can also grow on your skin. This type of infection leads to painful, red, and swollen skin. You could also get ulcers with a thick gray coating.

But this kind of infection doesn’t usually affect other organs in the body.

Without treatment, respiratory diphtheria (the type that infects body parts involved in breathing) can lead to severe health problems, like:

Some doctors diagnose the disease based on someone’s signs and symptoms. For example, if a child is sick and has a sore throat with a gray coating on their tonsils and throat, the doctor may suspect diphtheria.

They can do tests, too. They may swab the back of your throat or nose and have a lab check it for the bacteria that bring on diphtheria. If you have an open sore or ulcer, they can take a sample from that and get it tested, too.

If the doctor thinks you have respiratory diphtheria, they may start giving you treatment before your test results come back to help you avoid health complications.

Diphtheria treatments include:

  • Medications. Your doctor will give you drugs to combat the toxin that the bacteria makes. They’ll give you these medicines with a shot or an IV. You’ll also need to take an antibiotic – typically penicillin – to kill any bacteria still in your system.
  • A ventilator. You’ll only need this if your symptoms are very severe and make it hard to breathe.
  • Bedrest. Typically, you’ll need to rest for 4 to 6 weeks.
  • Isolation. No one can come near you while you’re still infectious.

The doctor will also need to treat your close family members if you’re diagnosed with diphtheria. That involves making sure they all have the vaccine against diphtheria and giving them booster shots if they do. They’ll also get antibiotics to make sure that the bacteria doesn’t spread.

If you get treatment, it’s possible to fully recover from diphtheria. Your recovery time will usually take from 4 to 6 weeks.

Even with treatment, though, some people don’t recover. Children under 5 years old and adults over 60 have worse odds of dying from the disease.

The CDC says that with treatment, about 9 in 10 people will survive a case of respiratory diphtheria. But up to half of people with the disease who don’t get treatment for it can die from it, the agency says.

The most important way to prevent it is to get a diphtheria vaccine and stay up to date on your shots.

Diphtheria vaccines are available for newborns as well as adults. In most countries, they’re part of the standard vaccination process for all newborn babies.

There are at least four vaccines for diphtheria in use in the U.S. Each of these also prevents tetanus, and two of them protect against whooping cough (pertussis), too.

The vaccines are:

  • DTaP: Helps prevent diphtheria, tetanus, and pertussis
  • DT: Helps prevent diphtheria and tetanus
  • Tdap: Helps prevent tetanus, diphtheria, and pertussis
  • Td: Helps prevent tetanus and diphtheria

Babies and children under 7 years old get DTaP or DT. Older kids and adults get Tdap and Td. Talk to your doctor to learn what’s best for you or child.

Doctors have schedules for when to give you or your child the series of shots, which include booster shots that you get after the first injections.

After adolescence, you can get a diphtheria booster every 10 years. You should always get the booster before traveling to parts of the world that have high rates of diphtheria.

You should also get the vaccine during every pregnancy, regardless of whether you’ve gotten it before.

Call your doctor right away if you or any of your family members have been near someone with diphtheria. You should double-check your vaccination history and get a new booster if you haven’t had one in 10 years.

Yes, but most of the possible side effects are mild.

In general, it’s possible to get a fever or have pain or skin redness where you got jabbed.

It’s rare, but some people have an allergic reaction to the vaccine.

Diphtheria was first named in 1826, but it has existed for a lot longer.

It used to be a major problem in the U.S. until the vaccine was developed and put into use in the 1920s.

Before the vaccine came out, there were hundreds of thousands of cases throughout the country each year. In 1921, for example, there were over 15,000 deaths in the U.S. alone from diphtheria.

Today, there are still thousands of new cases of diphtheria around the world each year, and researchers believe that it’s underreported in the countries where infection rates are highest.