Diphtheria

What is diphtheria?

Diphtheria is a serious disease caused by the bacterium called Corynebacterium diphtheriae. The bacterium produces a toxin (poison) that can cause serious illness. The disease can affect the nose, throat, or skin, and it can be deadly. Cases of diphtheria are very rare in the United States because of vaccination.

Who gets diphtheria?

Diphtheria is a rare disease in the United States. It is most likely to occur in unvaccinated people who travel to countries where the disease is more common.

How is diphtheria spread?

Diphtheria bacteria can live in the mouth, nose, throat, or skin of infected individuals. People most commonly spread the bacteria by coughing or sneezing. People can also get infected from touching open sores or ulcers caused by the bacteria.

What are the symptoms of diphtheria?

Symptoms of diphtheria depend on the affected part of the body. Respiratory diphtheria is a very serious condition. Symptoms include sore throat, mild fever, chills, and sometimes enlarged lymph nodes in the neck. A thick, gray coating called a “pseudomembrane” may form in the back of the nose or throat making it hard to breathe or swallow. Diphtheria skin infections rarely cause severe issues. However, they can cause painful open sores or ulcers.

How soon after exposure do symptoms appear?

It usually takes 2 to 5 days for symptoms to appear after someone has been exposed to the bacteria that makes diphtheria toxin.

How long can a sick person carry diphtheria?

Testing is needed to confirm that a person is no longer carrying diphtheria. After starting antibiotics, the infected person usually becomes noncontagious in 48 hours. Antibiotics should be continued until the infected person tests negative for diphtheria. If untreated, an infected person can be contagious for up to two to four weeks.

How is diphtheria diagnosed?

Testing involves swabbing the skin wound or the back of the throat and nose. Healthcare providers send the samples to a lab for testing. Laboratorians try to culture (grow) to identify any bacteria. If C. diphtheriae grow, then the laboratorians have to test to see if the bacteria make diphtheria toxin.

What is the treatment for diphtheria?

Certain antibiotics can be prescribed for the treatment of diphtheria. Diphtheria antitoxin may be available to prevent the disease from getting worse.

Do people who have been in contact with someone with diphtheria need to be tested and treated?

Close contacts of someone with diphtheria should receive antibiotics to prevent them from getting sick. They should also be monitored for illness, tested for diphtheria, and vaccinated if their diphtheria vaccines are not up to date.

How can diphtheria be prevented?

The best way to prevent diphtheria is to get vaccinated. There are three types of combination vaccines that include protection against diphtheria: DTaP, Td, and Tdap. The DTaP vaccine also helps protect against tetanus and whooping cough (pertussis). DTaP is given starting at approximately two months of age. Multiple doses are needed to ensure protection. Immunity wanes over time. Adolescents and adults are recommended to receive a booster vaccination called Tdap. After receiving Tdap, people should receive Td vaccine every 10 years. Talk to a vaccine provider if you have questions about diphtheria vaccines.

How can I learn more about diphtheria?

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Last Updated: January 9, 2025