Pronounced: Dif-THEER-e-uh


Diphtheria is a life-threatening infection. It can cause heart, nerve, and kidney damage. It needs to be treated right away.


This illness is caused by certain bacteria. It spreads from person-to-person contact. This can happen by:

  • Inhaling bacteria after a person coughs or sneezes
  • Using personal items such as tissues or drinking glasses
  • Having skin contact

Risk Factors

Things that raise the risk are:

  • Not having had:
    • A diphtheria vaccine, or
    • A booster dose in the past 10 years
  • Having a weak immune system


Symptoms of diphtheria may be mild or severe.

They may include:

  • A gray coating in the back of the throat
  • Sore throat or problems swallowing
  • Fever
  • Cough
  • Swollen lymph glands in the neck
  • Breathing problems
  • Tiredness

Swollen Glands in the Neck

Swollen lymph node
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The doctor will ask about your symptoms and health history. A physical exam may be done. A nose or throat swab can confirm the diagnosis.


Diphtheria will be treated right away, even if test results are not ready.

Treatment includes:

  • An antitoxin to stop damage to the body
  • Antibiotics to treat the infection
  • Isolation and bed rest


A vaccine will prevent the disease.


Centers for Disease Control and Prevention
National Institute of Allergy and Infectious Diseases


Caring for Kids—Canadian Paediatric Society
Public Health Agency of Canada


Diphtheria. Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/vaccines/pubs/pinkbook/dip.html. Accessed February 2, 2021.
Diphtheria. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/diphtheria. Accessed Februsary 2, 2021.
Immunization schedules. Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/vaccines/schedules/index.html. Accessed February 2, 2021.
Sharma NC, Efstratiou A, et al. Diphtheria. Nat Rev Dis Primers. 2019;5(1):81.
Td (tetanus, diphtheria) VIS. Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/vaccines/hcp/vis/vis-statements/td.html. Accessed February 2, 2021.
Tdap (tetanus, diphtheria, pertussis) VIS. Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/vaccines/hcp/vis/vis-statements/tdap.html. Accessed February 2, 2021.
Last reviewed September 2020 by David L. Horn, MD, FACP
Last Updated: 2/2/2021

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