What is diphtheria?

Diphtheria is an infectious disease. It's usually caused by the bacteria (germ) called Corynebacterium diphtheriae. It most often affects your upper respiratory tract — your nose, throat and tonsils.

When you catch diphtheria, the bacteria releases a toxin (poison) into your body. This toxin can affect your airways and cause a membrane to grow across your windpipe. This makes breathing difficult. If the membrane blocks your windpipe, it can lead to suffocation and death.

Diphtheria can be life-threatening, but due to immunisation it is rare in Australia.

What are the symptoms of diphtheria?

The symptoms of diphtheria depend on where the infection (germ) is in your body.

Diphtheria can give you:

• a sore throat
• loss of appetite
• mild fever

Within 2 to 3 days, a membrane can form over your throat. This can cause:

• swallowing problems
• breathing problems

It often causes the glands in your neck to swell. This is sometimes called 'bull neck'.

A less serious form of diphtheria causes skin sores to form. These form large ulcers that are slow to heal. This form of the disease is more common in tropical areas.

Diphtheria symptoms usually appear 2 to 5 days after coming into contact with the bacteria.

What causes diphtheria?

Diphtheria is usually caused by Corynebacterium diphtheriae. It can also be caused by other strains of corynebacterium, including Corynebacterium ulcerans.

How is diphtheria spread?

Diphtheria is spread by respiratory droplets. Respiratory droplets are the small droplets that come out of your nose and mouth when you cough or sneeze.

You can also catch diphtheria if you touch:

• things an infected person has coughed or sneezed on
• an infected person's skin sores
• materials soiled by an infected person

Practising good hygiene can help to stop diphtheria from spreading.

When should I see my doctor?

You should see your doctor if you have diphtheria symptoms or have been close to someone who has diphtheria.

How is diphtheria diagnosed?

Your doctor will ask you about your symptoms and look in your mouth. They will look for a greyish white membrane in your throat. They may ask if you've been close to someone who has diphtheria.

If they suspect that you have diphtheria, they will organise for a throat swab to be taken. Or if you have a suspected skin infection, a skin swab will be taken.

Diphtheria is a notifiable disease. This means that the doctor who diagnoses diphtheria needs to report the case to the local health authorities. They will take steps to prevent or control an outbreak.

Since diphtheria is very contagious, this usually involves a process called contact tracing. Contact tracers will speak with you to identify anyone who has had close contact with you recently.

How is diphtheria treated?

Diphtheria is treated with antibiotics. Special treatment with diphtheria anti-toxin may also be needed. This helps to kill the bacteria and stop toxin production.

You may need treatment in hospital.

If you have diphtheria, you will need to isolate until you are no longer infectious. This helps to stop the disease spreading.

Can diphtheria be prevented?

Vaccination is the most effective way to prevent diphtheria.

The diphtheria, tetanus and whooping cough (pertussis) vaccines are given together. This vaccine is called 'DTP'.

About the DTP vaccine

To find out more about diphtheria immunisation, talk to your doctor.

Complications of diphtheria

Diphtheria can cause long-term:

• inflammation of the heart muscle — which can lead to heart failure
• neurological (brain and nerve) problems — which can cause paralysis
• kidney problems

You may need medicines to treat complications of diphtheria.

Even with treatment, people sometimes die from diphtheria.

Resources and support

Find out more about the National Immunisation Program.

If you are concerned about diphtheria you can call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with 24 hours a day, 7 days a week.