Diphtheria is a very contagious infection caused by toxic strains of the bacteria Corynebacterium diphtheriae and Corynebacterium ulcerans. It usually affects the nose, throat and tonsils (respiratory diphtheria) but can also affect the skin (cutaneous diphtheria).
Respiratory diphtheria is very serious. The bacteria release a toxin that can affect your airways and cause a membrane to grow across your windpipe, making breathing difficult. The toxin can also harm your heart, kidneys and nerves.
Diphtheria was a common cause of death in Australian children until the 1940s. Today, cases are rare due to high vaccination rates, and most diagnoses in Australia occur in people who have recently travelled overseas.
Symptoms typically develop 2–5 days after exposure, though in some cases they may take up to 10 days.
The symptoms depend on where the infection occurs in your body.
In respiratory diphtheria, the first symptoms usually include:
Within 2–3 days, a greyish-white film may form over the throat and tonsils, making it difficult to swallow or breathe. The neck may also swell.
Cutaneous diphtheria causes sores on the skin, often on the legs. These can turn into larger ulcers and may heal slowly. This form is more common in tropical climates.
In rare cases, diphtheria can inflame the heart, kidneys, and nerves, sometimes causing long-term damage or death.
See your doctor immediately if you, or your child, have any diphtheria symptoms. Tell your doctor if you have been overseas recently.
If you, or your child, are having difficulty breathing, this is an emergency—call Triple Zero (000) or go to the Emergency Department.
Diphtheria usually spreads in the air when an infected person coughs or sneezes.
It can also spread by touching saliva, mucus, or skin sores from an infected person, including contaminated objects. Rarely, it can spread from animals through contact or consuming raw milk.
People with diphtheria can be infectious for up to 4 weeks after symptoms start. Antibiotic treatment can shorten this period.
Anyone who is not fully vaccinated is at risk. People travelling to countries with low vaccination rates, such as parts of the South Pacific, South and South-East Asia, the Middle East, Eastern Europe, South and Central America, may be at higher risk.
Vaccination is the best protection against diphtheria.
Vaccinations are part of the childhood immunisation schedule and are safe, free, and effective. Children should be vaccinated at:
Children receive a booster at 11-13 years through the NSW School Vaccination Program. Vaccines against diphtheria, tetanus, and pertussis (dTpa) are given together.
Diphtheria boosters are recommended for:
High community vaccination rates help protect everyone. Vaccinated people may still get diphtheria, but usually less severe illness.
Diphtheria is diagnosed through a swab test, usually from the throat. Skin swabs may be taken if sores are present, and samples are sent to a laboratory.
Treatment includes antibiotics. Serious cases may require hospitalisation and antitoxin medication. Vaccination is recommended for unvaccinated individuals to provide protection against future infection.
If diagnosed, you should:
If you are concerned about symptoms, contact your doctor or call healthdirect at 1800 022 222 for free 24/7 advice.
Diphtheria is a notifiable disease in NSW. Doctors, pathology providers, and certain services must report cases to the local public health unit. This helps identify outbreaks and provides advice to stop the spread. All information remains confidential.
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