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What Is Diphtheria? Symptoms, Causes & Prevention

What is Diphtheria?

Diphtheria(白喉) is a vaccine-preventable infection caused by bacterial strains called Corynebacterium diphtheriae. The disease produces a toxin causing people to get ill by contaminating the respiratory tract and the skin.

Diphtheria cases have decreased drastically ever since the production of vaccines. However, in some parts of the world, there are still some reported outbreaks of diphtheria.


What Are the Symptoms of Diphtheria?

Symptoms of diphtheria can be present 2 to 5 days after being infected. The most common symptoms are:

  • Fever of 38 degrees Celsius or above.
  • Muscle aches and muscle weakness.
  • Sore throat.
  • Headache.
  • Swollen glands in your neck.
  • Difficulty breathing or swallowing.

Symptoms of diphtheria can vary depending on the type of infection:

Respiratory Diphtheria

Respiratory Diphtheria is when bacterial strains infect the respiratory system. The respiratory system involves organs and tissues that facilitate breathing, including the airways, lungs, and blood vessels.

When bacteria attack the lining of the respiratory system, they can grow toxins that kill healthy tissues, leading to dead tissues accumulating to form a thick and grey layer in the throat or nose. The blockage of tissues in the respiratory system can cause difficulty in breathing and swallowing.

Furthermore, it can cause weakness in the respiratory tract and a sore throat, mild fever, or the neck's glands becoming swollen.

Diphtheria Skin Infection

Also referred to as skin (cutaneous), diphtheria is when the bacterial strains infect the skin. The infection can cause pain, redness, swelling, ulcers and open sores. Diphtheria skin infections are less likely to lead to severe complications.

Common symptoms include having pus-filled blisters on your legs, feet or hands or having large ulcers that are surrounded by red, sore-looking skin. Since the symptoms of diphtheria infection can be mild with no extreme symptoms, individuals could be unaware of the infection while carrying the diphtheria bacteria.


Diphtheria Treatment

Antibiotics such as penicillin or erythromycin can be used to treat diphtheria. An antitoxin can also be provided to remove the toxin produced from diphtheria in the body. The antitoxin drug is usually injected into a vein or muscle by medical professionals.

The best treatment is prevention by receiving the vaccination, as diphtheria can have severe complications.


How Is Diphtheria Transmitted?

It can spread from person to person through the infection of the respiratory tract. For example, coughing or sneezing can spread airborne droplets. It can also transmit through contact with open sores or ulcers or through sharing or touching personal items such as hand towels, utensils, cups, clothing, or bedding with an infected person.


Holding diphtheria vaccine


How To Prevent Diphtheria?

Vaccines are the best way to prevent diphtheria. There are different types of combination vaccines used to protect individuals against diphtheria and other vaccine-preventable diseases. Some examples are:

  • Diphtheria and tetanus (DT) vaccines
  • Diphtheria, tetanus, and pertussis (DTaP) vaccines
  • Tetanus and diphtheria (Td) vaccines
  • Tetanus, diphtheria, and pertussis (Tdap) vaccines

You can learn more about the different combinations of vaccines in our tetanus, diphtheria and pertussis blog.

In Hong Kong, the Diphtheria, Tetanus, Acellular Pertussis & Inactivated Poliovirus Vaccine is available through the Childhood Immunisation Program.


What Are the Possible Diphtheria Complications?

If left untreated, diphtheria can lead to complications. This includes difficulties with breathing and organ damage, such as the heart and the nerves. The toxin produced by diphtheria can also damage tissue cells at the site of infection. The disease can also inflame the heart muscle, leading to heart complications.



Diphtheria is a vaccine-preventable infection caused by bacterial strains called Corynebacterium diphtheriae. Symptoms of diphtheria depend on the type of infection and can be prevented by vaccines. Speak to your doctor for healthcare advice and available vaccinations.

Not sure which vaccines you need? Get a free, personalised immunisation schedule with our vaccine calculator to stay up-to-date with your health. You can also browse our health information knowledgebase to learn more about other vaccine-preventable diseases.

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  1. Centers for Disease Control and Prevention. (2020). ‘Diphtheria: Causes and Spread to Others.’ CDC. 26 May 2020. Available from: <> [Accessed 26 October 2021].
  2. Mayo Foundation for Medical Education and Research. (2020). ‘Diphtheria.’ Mayo Clinic. 1 January 2020. Available from: <> [Accessed 26 October 2021].
  3. National Health Service. (2018). ‘Diphtheria.’ NHS. 28 February 2018. Available from: <> [Accessed 26 October 2021].
  4. Centers for Disease Control and Prevention. (2020). ‘Symptoms of diphtheria.’ CDC. 26 May 2020. Available from: <> [Accessed 26 October 2021].
  5. Cleveland Clinic. (2020). ‘Respiratory System’ 24 January 2020. Available from: <,waste%20gases%20like%20carbon%20dioxide> [Accessed 26 October 2021].
  6. New York State Department of Health (2012). ‘Diphtheria.’ January 2020. Available from: <> [Accessed 26 October 2021].
  7. Centers for Disease Control and Prevention. (2020). ‘Diphtheria vaccination.’ CDC. 22 January 2020. Available from: <> [Accessed 26 October 2021].

Topics: Vaccinations

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