Overview

Diphtheria is a contagious disease caused by toxin-producing bacteria, Corynebacterium diphtheriae, mainly affecting the upper respiratory tract and sometimes the skin. Symptoms include sore throat, fever, swollen glands and weakness.

The bacterium produces a toxin that can cause serious complications, such as heart failure or paralysis, without prompt treatment.

Diphtheria is a vaccine-preventable disease. Multiple doses and booster doses are needed to produce and maintain immunity.

Those who are not immunized, or are under-immunized, are at risk of the disease.

Without prompt diphtheria antitoxin administration and antibiotic treatment, diphtheria can be fatal in 30% of cases. Do not wait for lab confirmation to start treatment. Children under 5 years old are at higher risk of dying. They have less developed immune systems and smaller airways which can be more easily blocked by diptheria’s characteristic throat swelling.

Transmission

Diphtheria spreads from person-to-person, mostly through respiratory droplets when an infected person coughs or sneezes, and less frequently by direct contact.

The incubation period is usually from 2 to 5 days.

Some people may not develop disease manifestations but can still transmit the bacteria to others.

Symptoms

Typical symptoms of the infection include:

sore throat

fever

swollen neck glands

weakness.

Within 2–3 days from infection, dead tissue in the respiratory tract forms a thick grey coating that can cover tissues in the nose, tonsils and throat, making it hard to breathe and swallow and leading to airway obstruction in severe cases.

Most severe cases of disease and deaths from diphtheria occur as a result of the damaging effects of the diphtheria toxin which can cause significant harm to the heart, nerves and other vital organs.

For health care workers: Look for the presence of danger signs (impending airway or circulatory failure). If any are present, call for urgent supportive treatment.

Any sign of respiratory distress, such as inspiratory stridor (a high-pitched sound when breathing in), fast breathing, chest indrawing (chest sinking in with each breath), use of accessory muscles (extra muscles around the neck and ribs used for breathing) and restlessness are warning signs of impending airway obstruction and of the need to secure the airway.

Lethargy (extreme tiredness), cyanosis (bluish skin) or SpO2 (oxygen saturation) below 90% are serious warning signs indicating severe airway blockage and require urgent securing of the airway.

Any sign of shock, such as capillary refill taking longer than 3 seconds, cold extremities, a fast pulse rate or low blood pressure, indicate an urgent medical situation.

Who is at risk?

Any non-immune person (not vaccinated or under-vaccinated) can become infected. Diphtheria tends to resurge when immunization coverage is low.

Overcrowding in residential camps increases the risk of diphtheria infection. Close human contact facilitates the spread of the bacterium through respiratory droplets, especially in confined living spaces.

Treatment and management

Importance of early treatment: The risk of complications or death decreases considerably if appropriate treatment, such as antitoxin administration and antibiotics, is provided early in the course of the illness.

Lab diagnosis: A swab from the back of the throat or nose should be taken for testing for diphtheria-causing bacteria. Do not wait for lab confirmation to start treatment.

Diphtheria antitoxin (DAT) and antibiotics are the key treatments for diphtheria.

Diphtheria antitoxin (DAT) neutralizes the toxins circulating in the blood. DAT should be administered immediately to probable cases with respiratory diphtheria (sore throat, low-grade fever and presence of a thick gray covering on the tonsils, throat or nose) based on clinical diagnosis. DAT should be administered in a closely monitored setting where appropriate medical interventions are available.

Antibiotics stop bacterial replication, which reduces toxin production. They also help eliminate the bacteria from the body faster and prevent it spreading to others.

Anyone who has had diphtheria should be vaccinated once the acute phase of the illness is over.

Resource-limited alternatives: In settings where antitoxin and antibiotics are unavailable, immediately isolate the individual to prevent further spread. Supportive care, such as ensuring adequate hydration (e.g. oral rehydration solutions if clean water is scarce), is critical.

Managing complications: Close monitoring and supportive care are essential to prevent and treat complications such as airway obstruction and myocarditis (inflammation of the heart). For patients facing imminent airway obstruction, seek urgent medical help to secure airways and follow airway management protocols.

Prevention

Vaccination

Prioritizing vaccination is key. Diphtheria is preventable with a vaccine typically given in combination with tetanus, pertussis (whooping cough), hepatitis B, Hemophilus influenzae b and polio vaccines.

Health care workers should follow standard contact and droplet precautions

At triage, immediately place patients with symptoms of acute respiratory infection in a separate area until examined. If diphtheria is suspected, group patients with the same probable diagnosis. Keep the isolation area separate from other patient care areas.

Physical distancing: Maintain one metre between patients. Ensure patient care areas are well ventilated.

Contagion: After 48 hours of effective antibiotic therapy have been completed the disease is usually not contagious. Consider discharge at this time if the patient is improving.

Post-discharge: After discharge, restrict contact with others until completing antibiotic therapy. Stay within your designated living area and avoid communal activities until the treatment course is complete.

Hygiene and dietary support

Encourage hygiene practices: Promote good hygiene practices, such as regular handwashing and mask use if symptoms appear, especially in crowded settings.

If sinks are not available in patient areas, Veronica buckets (portable handwashing stations) can be installed to provide water for hand hygiene close to the point of care. Alternatively, a handwashing basin, soap and a jug of clean water can be placed on a trolley used for ward rounds to encourage handwashing as often as needed between patient contacts.

When soap, clean water and alcohol-based hand rubs are unavailable, the following options can be considered:

Sodium hypochlorite may be added to water to achieve an end formulation of 0.05% sodium hypochlorite for use in dispenser containers for hand hygiene.

Sodium hypochlorite solution becomes inactive when exposed to air and organic materials. If this method is used during supply shortages, it is recommended that the solution be prepared in small batches daily and dispensed from closed containers.

Sodium hypochlorite added to water with a high saline content (seawater) is also an option, as long as an end formulation of 0.05% sodium hypochlorite is achieved. Other water sources, such as rainwater, may be considered.

Consider using other hand hygiene products that have antimicrobial properties, such as waterless no-rinse hand soaps.

Health care workers should provide appropriate nutritional support. Encourage the child to eat and drink. If the child has difficulty swallowing, consider using a nasogastric feeding tube, but be aware there is a risk of causing airway problems. The nasogastric tube should be placed with extreme caution by an experienced clinician or an anaesthetist, if available. Avoid frequent examinations and invasive procedures when possible.

Preventive measures for contacts: Individuals who have been in contact with diphtheria cases should receive prophylactic (preventive) antibiotics. It is essential to check the immunization status of all contacts. If they are not fully vaccinated, they should be offered the vaccine. In resource-limited settings, where antibiotics and vaccines may not be readily available, coordinating with local health authorities or international health organizations for emergency medical support is crucial.

Community engagement and health care coordination

Surveillance and rapid response

Early detection and containment: Monitor communities for symptoms of diphtheria and quickly isolate suspected cases to prevent spread.

Experience sharing: Use lessons from previous outbreaks and international guidelines to implement rapid response strategies effectively.

Community engagement

Building strong community awareness and education on diphtheria symptoms, transmission and prevention helps in early detection and control of outbreaks.

Engage community leaders and health care workers in outreach programmes to spread knowledge and enhance community readiness.

Share vital information about hygiene practices, symptom recognition and the importance of immediate health care consultation within your community.

Sources

Clinical management of diphtheria: guideline. Geneva: World Health Organization; 2024 (https://www.who.int/publications/i/item/WHO-DIPH-Clinical-2024.1).

Diphtheria. Geneva: World Health Organization; 2024 (https://www.who.int/news-room/fact-sheets/detail/diphtheria#:~:text=Overview,transmit%20the%20bacteria%20to%20others).

Infection prevention and control and water, sanitation and hygiene measures in health-care settings and shelters/congregate settings in Gaza: technical note. Geneva: World Health Organization and United Nations Children’s Fund; 2024 (https://www.unicef.org/sop/media/3681/file/Infection%20prevention%20%20and%20control%20and%20water,%20%20sanitation%20and%20hygiene%20%20measures%20in%20health-care%20%20settings%20and%20shelters%20congregate%20settings%20in%20Gaza.pdf).

Operational protocol for clinical management of diphtheria. Bangladesh: World Health Organization; 2017 (https://www.who.int/docs/default-source/documents/publications/operational-protocol-for-clinical-management-of-diphtheria.pdf?sfvrsn=70868342_1).