Diphtheria is a highly contagious, infectious disease caused by a bacterium called Corynebacterium diphtheriae. People with diphtheria have serious breathing and swallowing problems, and they may develop sores on their skin. Due to a successful vaccine and improved living conditions, diphtheria is no longer prevalent in the United States.


What is diphtheria?

Diphtheria is a contagious infection caused by a bacterium called Corynebacterium diphtheriae. The bacterium releases a toxin that causes a buildup of grey tissue in your throat, leading to problems with swallowing and breathing.

In warmer climates, someone with diphtheria might also develop skin sores that will not heal and may be covered with the grey tissue. This type of diphtheria (called cutaneous diphtheria) also happens sometimes in the U.S. when people live in crowded and unhealthy conditions.


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When was the diphtheria epidemic?

In the U.S., the diphtheria epidemic peaked in 1921 with 206,000 cases.

Is diphtheria still around today?

Diphtheria isn’t common in the U.S. because living conditions have improved, and children are routinely given a diphtheria vaccine. In the past, a large number of people died from diphtheria in the U.S. In other countries where vaccinations aren’t given, the disease still exists. As a result, there’s still a potential for diphtheria to cause problems in the U.S.

Where is diphtheria found?

In many areas of the world, diphtheria is still considered an endemic (an outbreak that’s limited to a certain region). This includes Asia, the Dominican Republic, Eastern Europe, Haiti, the South Pacific and the Middle East.


What are the different types of diphtheria?

There are two main types of diphtheria, including classical respiratory and cutaneous:

  • Classical respiratory diphtheria: The most common type of diphtheria, classical respiratory diphtheria may affect your nose, throat, tonsils or larynx (voice box). Symptoms can vary depending on where the affected membranes are located in your body. Some people call this condition pharyngeal diphtheria (diphtheria of the throat).
  • Cutaneous diphtheria: The rarest type of diphtheria, cutaneous diphtheria is characterized by skin rash, sores or blisters, which can appear anywhere on your body. Cutaneous diphtheria is more common in tropical climates or crowded places where people live in unhealthy conditions.

How do you get diphtheria?

You can catch diphtheria through airborne droplets that contain bacteria (spread by sneezing, coughing and spitting) or by touching something that has bacteria on it. It is also possible that an infected person could transmit the disease through an open sore touched by someone else, or touching clothes that someone else touches. It’s possible to get diphtheria more than once.


Who’s at risk of developing diphtheria?

Anyone who isn’t protected by the vaccine and comes in close contact with an infected person can develop diphtheria.

Symptoms and Causes

What are the symptoms of diphtheria?

Common diphtheria symptoms include:

  • Throat pain.
  • Weakness or fatigue.
  • Fever.
  • Swollen neck glands.
  • Problems breathing due to tissues obstructing your nose and throat.
  • Difficulty swallowing (dysphagia).
  • Nerve, kidney or heart problems (if the bacteria enters your bloodstream).

An infected person typically shows signs of diphtheria around two to five days after exposure. The length of time for symptoms to show can be anywhere from one to 10 days after exposure.

What causes diphtheria?

Diphtheria is caused by bacteria adhering to the lining of your respiratory system. These bacteria generate a toxin that damages your respiratory tissue cells. Within two or three days, the tissue left behind forms a bulky, grey coating. This coating has the potential to cover tissues in your voice box, throat, nose and tonsils. For the infected person, breathing and swallowing become hard to do.

Is diphtheria contagious?

Yes. Diphtheria is a highly contagious disease that’s spread through airborne droplets or contaminated personal items.

Diagnosis and Tests

How is diphtheria diagnosed?

Your healthcare provider will make a diagnosis based on symptoms and a lab test. They’ll use a swab to take a sample from the back of your throat or from a sore. This swab then goes to a lab for diagnosis.

Management and Treatment

How is diphtheria treated?

Diphtheria treatment begins immediately — sometimes even before the lab test results are confirmed. Your healthcare provider will prescribe diphtheria antitoxin to stop damage to your organs. They’ll also prescribe antibiotics, typically penicillin or erythromycin, to fight infection.

People with diphtheria are kept in isolation to prevent others from becoming infected. An infected person is no longer contagious around 48 hours after taking antibiotics. When treatment ends, tests will be run again to make sure the bacteria are gone. Once the bacteria are gone, you will get a vaccine to prevent future infections.

What are the complications associated with diphtheria?

Diphtheria can result in a number of long-term complications, including:

  • Blockage of your air passages.
  • Injury to your heart muscle.
  • Injury to your nerves.
  • Sluggishness or lethargy.
  • Paralysis (being unable to move).
  • Lung infection or loss of lung function.


Can I prevent diphtheria?

Yes. There are many different vaccines in the U.S. that are designed to stop diphtheria. Several of them protect you against multiple infections at once, such as pertussis (whooping cough) and tetanus as well as diphtheria. There are different immunization schedules for getting the series of shots, including booster shots after the first ones are given.

In general, vaccine side effects might include fever, pain or redness at the needle site, and rarely, an allergic reaction to the vaccine itself.

Outlook / Prognosis

What can I expect if I have diphtheria?

Treatment for diphtheria can be effective. But, even with treatment, roughly 1 out of 10 people might die. For those without treatment, one out of two patients may die. Vaccination is the best choice. If you haven’t been vaccinated, make an appointment with your healthcare provider.

How long does diphtheria last?

For people with diphtheria, it usually takes about two to three weeks for treatment to be effective. Any skin ulcers could take two or three months to fully heal, though scarring may be permanent.

Is diphtheria curable?

Yes. When treated immediately, diphtheria is managed successfully with antitoxins and antibiotics. Vaccination can prevent diphtheria altogether.

Living With

When should I see my healthcare provider?

Call your healthcare provider immediately if you or a family member has been exposed to diphtheria. If you’re not sure whether you’ve been vaccinated against diphtheria, schedule an appointment right away.

Additional Common Questions

Why is the back of my throat grey?

Just because the back of your throat is grey, it doesn’t necessarily mean you have diphtheria. Other conditions can cause grey patches on the back of your throat, including acute pharyngitis (sore throat) and tonsillitis. If you develop grey patches on the back of your throat, call and schedule an appointment with your healthcare provider. They can determine the cause and design a personalized treatment plan to meet your needs.

A note from Cleveland Clinic

Diphtheria is a serious, life-threatening illness that must be treated immediately. If you haven’t already been vaccinated against diphtheria, or if you’re not sure your vaccinations are up to date, schedule an appointment with your healthcare provider right away.

Medically Reviewed

Last reviewed on 04/06/2022.

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