Diphtheria: Symptoms, Causes, Treatment and Prevention
mark ogujiuba Diphtheria: Symptoms, Causes, Treatment and Prevention
Diphtheria is a severe bacterial infection which can involve the nose, the throat and, in a number of instances, the skin; it may become dangerous since some types of the bacteria produce a toxin that is capable of damaging the heart, the nerves and other organs.
The good news is that diphtheria can be prevented by means of vaccination. Furthermore, early diagnosis and the use of proper treatment can also lower the chance of serious complications.
Even though vaccination has greatly reduced the number of cases of diphtheria in many parts of the world, the disease has not yet gone away. Outbreaks happen when vaccination coverage drops, which leaves more people at risk of getting the disease.
If you want to see a more general overview of the role of vaccination in disease prevention, refer to our article titled [Preventive Health: Definition, Importance, and Ways to Prevent Disease]. Read MedsLearn's preventive health guide
This article explains what diphtheria is, what causes it, how it spreads, the symptoms you should look out for, who is most at risk, how it is treated, how vaccination can prevent it, and what action to take if you or a close member of your family has been exposed.
What Is Diphtheria?
Diphtheria is an infectious disease caused by strains of the bacterium known as Corynebacterium diphtheriae which produces toxins.
The bacteria usually affect the upper respiratory tract, the nose, and throat, and they are also able to cause skin infections.
The main worry is the diphtheria toxin made by certain strains of the bacteria; it is capable of damaging cells and tissues and of spreading beyond the initial site of infection.
In cases of diphtheria affecting the respiratory system, the toxin causes damaged tissue to produce a thick grey or white coating, referred to as a pseudo-membrane, in the throat or nose; this membrane can result in difficulty with both breathing and swallowing.
The toxin may also have an effect on other organs, especially the heart and the nervous system.
What Causes Diphtheria?
Diphtheria results from an infection with Corynebacterium diphtheriae, a bacterium that produces toxins.
It is necessary to realize that bacteria and toxins have different roles.
It is the bacteria that cause the infection and the toxin that is behind many of the serious complications connected with diphtheria.
This toxin is capable of damaging the tissues surrounding the throat and, once it has entered the bloodstream, can have an effect on organs located elsewhere in the body.
How is diphtheria transmitted?
Diphtheria can be transmitted from one person to another.
The bacteria may be transferred by respiratory droplets if an infected individual coughs or sneezes and having close contact with an infected person can increase the chances of it being transmitted.
Diphtheria can be transmitted by meeting skin sores or discharges from an infected person, and contaminated objects can also contribute to the spread.
Individuals who carry the bacteria, but who have only a few or no symptoms can also pass on the infection.
One reason why control of diphtheria requires more than just treating those who are visibly ill is that vaccination, surveillance, the early diagnosis and management of close contacts are all essential components of disease control.
If you want to know more about infectious diseases and the way in which they spread, see [Communicable and Non-Communicable Diseases: Two Illnesses, One Family, and a Lesson We All Need to Learn]. Read the MedsLearn communicable-disease guide
How long after infection do the symptoms of diphtheria appear?
The symptoms of diphtheria generally appear between 2 and 5 days after exposure to the bacteria.
Nevertheless, people do not show obvious symptoms. Those who are infected might have a mild case or no clear symptoms yet still be able to pass on the bacteria.
What are the signs of diphtheria?
The place where the diphtheria infection occurs in part determines the symptoms.
Symptoms of respiratory diphtheria
Common symptoms can include:
Sore throat
Fever
Weakness or tiredness
Swollen glands in the neck
Swelling of the neck
Difficulty swallowing
Difficulty breathing
A thick grey or white membrane in the throat or nose
At first the illness may appear to be a normal throat infection, and this can make it difficult to spot early on.
A worsening of the sore throat together with difficulty in breathing or swallowing, marked neck swelling, or the presence of a grey or white membrane all calls for an urgent medical evaluation.
Symptoms of skin diphtheria
Skin diphtheria may result in sores or ulcers on the skin, as it can look like other skin infections, making it essential to have a professional medical evaluation.
Skin diphtheria is usually less likely than respiratory diphtheria to result in serious complications, but it can still pass the bacteria to others.
What is the significance of the grey or white membrane in diphtheria?
A characteristic feature of diphtheria affecting the respiratory system is the presence of a thick grey or white film in the throat or nose.
It is referred to as a pseudo-membrane.
It arises from the damaged tissue and from other materials linked to the infection.
The membrane might interfere with both swallowing and breathing and could pass through some of the upper airways.
That is one of the reasons why people should not treat suspected diphtheria as a simple sore throat.
Can diphtheria cause the neck to swell?
Yes.
Swollen glands in the neck are a well-known symptom of respiratory diphtheria, and in more serious instances the swelling of the neck can become quite noticeable.
The presence of a sore throat, fever, enlarged neck glands, and a grey or white membrane should lead to concern regarding the possibility of respiratory diphtheria, especially if the person is not well vaccinated.
Why is diphtheria dangerous?
Diphtheria becomes dangerous mainly due to the toxins made by certain strains of the bacteria.
The toxin has the ability to damage the tissues at the site of the infection and can at the same time spread via the bloodstream.
Breathing problems
A membrane which develops in the respiratory tract can block the airway.
Severe obstruction can cause difficulty breathing and might necessitate urgent medical treatment.
Heart complications
The toxin associated with diphtheria is capable of harming the heart and leading to myocarditis, which is defined as inflammation and damage to the heart muscle.
Severe heart problems can happen either during or after the first infection.
Nerve problems
It also has the ability to affect the nervous system and lead to nerve damage.
Kidney and other complications
Severe diphtheria may also have an effect on other organs, such as the kidneys.
The WHO states that in cases among people who are not vaccinated and who do not get appropriate treatment, diphtheria can be fatal in about 30 percent of instances, with young children being at especially high risk.
Who Is Most Likely to Contract Diphtheria?
A person who is not sufficiently protected from diphtheria may contract it.
People at increased risk include those who are:
Unvaccinated
Incompletely vaccinated
No longer adequately protected
In close contact with someone who has diphtheria
Living in crowded conditions
Living in communities where vaccination coverage is low
The WHO points out that outbreaks become more likely as population immunity decreases.
Can adults contract diphtheria?
Yes.
Diphtheria is not merely a childhood disease.
Adults who have not had the vaccine or have not been properly vaccinated can also catch the disease.
It is especially important at the time of an outbreak since protection might be incomplete in those who never finished their vaccination course or who did not have the recommended booster doses.
Diphtheria in Children
Children who haven't had the recommended diphtheria-containing vaccines are especially vulnerable.
Parents and caregivers ought to ensure that children have their routine immunisations up to date and obtain medical advice if any of the vaccination doses have been missed.
Having a sore throat does not mean that a child has diphtheria; there are many illnesses which can cause both a sore throat and fever.
Symptoms including trouble breathing, difficulty in swallowing, marked swelling of the neck, or the presence of a grey or white membrane in the throat should be subject to immediate medical evaluation.
Is Diphtheria Contagious?
Yes.
Diphtheria can be passed from person to person by means of respiratory droplets and through close contact; skin infections can as well contribute to transmission by contact with infected sores or secretions.
That is the reason why individuals suspected of having diphtheria should have a quick medical evaluation and the proper infection-control precautions taken.
People who have had close contact may also have to be evaluated, receive preventive treatment, and have their vaccination status assessed.
How is diphtheria diagnosed?
When assessing possible cases of diphtheria, healthcare professionals take into account a number of factors.
These may include:
Symptoms and physical examination
The presence of a throat or nasal pseudo-membrane
Vaccination history
Recent exposure to someone with diphtheria
Laboratory testing
A healthcare professional can have samples taken from the nose, the throat, or from a skin lesion which is affected for the purpose of laboratory testing.
It is important not to wait for laboratory confirmation before starting treatment when diphtheria is strongly suspected. The World Health Organization advises against delay in beginning treatment since such a delay can increase the risk of complications.
How is diphtheria treated?
Diphtheria requires medical treatment.
Two of the key elements of treatment are diphtheria antitoxin and antibiotics.
Diphtheria antitoxin
DAT, also known as diphtheria antitoxin, is used for neutralizing the toxin, which is still circulating in the body.
Since the toxin is what causes most of the severe damage linked with diphtheria, it is important to give the antidote early if the disease is suspected.
Antibiotics
Antibiotics are used to get rid of bacteria.
They also help in reducing the production of further toxins and decrease the chance of the infection spreading to other people.
Supportive treatment
For certain individuals with serious illness, it may be necessary to have extra medical assistance, especially if there are problems with breathing or complications involving the heart, the nerves, or other organs.
Can diphtheria be treated at home?
Suspected cases of diphtheria must not be looked after at home unless they have been assessed by a medical professional.
A sore throat can have a number of different causes, but in the case of suspected diphtheria there must be a quick professional evaluation since the disease can advance rapidly and might lead to serious complications.
Do not use leftover antibiotics or take medicine prescribed to someone else.
The right course of treatment will depend on both the patient's clinical condition and the healthcare professional's assessment.
What are you supposed to do if you have been exposed to diphtheria?
If you've had close contact with a person who has been diagnosed with diphtheria, you should seek medical advice as soon as possible.
Close contacts may require:
Monitoring for symptoms
Preventive antibiotics
Testing
Review of vaccination history
Additional vaccination where appropriate
It is the WHO that recommends assessing people who have been in close contact with a case and giving them the appropriate preventive treatment since those who have been exposed might become infected or pass on the bacteria even before showing obvious symptoms of illness.
How is diphtheria prevented?
The best method of avoiding diphtheria is vaccination.
The diphtheria vaccine makes use of a harmless, inactivated version of the toxin, known as a toxoid. This enables the immune system to build protection against the toxin without causing diphtheria.
Diphtheria vaccination is generally given as one of combination vaccines rather than as a separate injection and, according to the type of vaccine and the national program, it can include immunity against a number of diseases such as tetanus, pertussis, hepatitis B, Haemophilus influenzae type b and polio.
Vaccination forms a vital component of preventive health since it helps to avoid disease before infection takes place.
How many doses of the diphtheria vaccine are required?
The recommendation is for a three-dose course of the diphtheria-containing vaccine in infancy and then for three booster doses in childhood and adolescence to help ensure long-term protection.
The specific schedules may vary between the various national immunization programs.
The childhood routine program in Nigeria consists of three doses of a diphtheria-containing pentavalent vaccine, with the recommended doses being at 6, 10 and 14 weeks of age as stated in the Nigeria Centre for Disease Control and Prevention's diphtheria information.
Parents ought to adhere to the present Nigerian immunization program and consult a healthcare professional if there have been any missed doses or if they need to carry out catch-up vaccination.
Why Is It Important to Have Booster Doses?
Protection from diphtheria must be kept up over time.
That is the reason why vaccination does not have to end with the first childhood doses.
Who suggests the administration of additional booster doses during childhood and adolescence as a means of maintaining longer-term protection?
Anyone who is unsure of their vaccination status should consult a healthcare professional instead of assuming that they are protected.
Can a person who has been vaccinated still contract diphtheria?
Although vaccination offers strong protection, it does not mean that infection is impossible.
Protection is based on getting the recommended doses and keeping immunity over time.
One reason why vaccination program stress both the initial doses and the booster doses is that...
High levels of vaccination also contribute to the protection of communities by decreasing the chances of the bacteria spreading.
Diphtheria in Nigeria
In recent years diphtheria has been a major concern for public health in Nigeria.
It was reported that from 1 January to 2 November 2025 Nigeria had 12,150 suspected cases of diphtheria, of which 8,587 were confirmed and 884 people died. During that reporting period, confirmed cases were reported in 240 Local Government Areas in 30 states.
The same source also stated that the outbreak had a disproportionate effect on children and adolescents and cited low vaccination coverage as one of the factors responsible for the ongoing transmission.
The numbers relate specifically to the 2025 reporting period and must not be taken as representing the actual number of cases in 2026.
Diphtheria has occurred in various states in Nigeria, and the Nigeria Centre for Disease Control and Prevention has stressed the importance of vaccination, the early identification of cases, reporting them and providing appropriate care for the cases and their close contacts.
This means that for people in Nigeria vaccination and getting timely medical treatment are especially important.
Diphtheria as compared with a common sore throat
It doesn't follow that every sore throat is a case of diphtheria.
Many common infections can cause:
Sore throat
Fever
Swollen glands
Cough
Weakness
Difficulty swallowing
Diphtheria is especially worrying when its symptoms are accompanied by findings such as a grey or white pseudo-membrane, marked neck swelling, or difficulty breathing.
The importance of having a vaccination record and having been in contact with a confirmed case should also be noted.
The explanation given below will help to illustrate the difference, but it must not be used for the purpose of diagnosing yourself.
Feature | Common throat infection | Diphtheria |
Sore throat | Common | Common |
Fever | May occur | May occur |
Swollen neck glands | May occur | May occur |
Grey/white pseudo-membrane | Not typical | Can occur |
Difficulty breathing | Possible in severe illnesses | Can become serious |
Heart or nerve complications from toxin | Not typical | Possible |
Preventable by diphtheria vaccination | No, depending on cause | Yes |
If diphtheria is suspected, it is all important to have a professional medical evaluation rather than attempting to make the diagnosis at home.
Common Myths About Diphtheria
Myth 1: Diphtheria only affects children.
False. Adults can also become infected when they are not adequately protected. (CDC: Diphtheria Vaccination)
Myth 2: Diphtheria has disappeared.
False. Diphtheria outbreaks still occur, particularly where vaccination coverage is inadequate. (WHO: Diphtheria)
Myth 3: Every sore throat is diphtheria.
False. Sore throats have many possible causes, so diagnosis requires proper medical assessment.
Myth 4: Antibiotics alone are always enough.
False. Treatment may also require diphtheria antitoxin and supportive care. (WHO: Diphtheria)
Myth 5: One vaccine dose provides lifelong protection.
Not necessarily. Diphtheria vaccination involves a primary series and booster doses to maintain protection. (WHO: Diphtheria)
When Should You Seek Urgent Medical Care?
Seek urgent medical attention if someone develops:
Difficulty breathing
Difficulty swallowing
A grey or white membrane in the throat or nose
Significant neck swelling
Fever and sore throat following close contact with someone who has diphtheria
Concerning symptoms in someone who is unvaccinated or incompletely vaccinated
The WHO recommends prompt treatment when diphtheria is suspected, because early management is important in reducing serious complications.
What Should You Do If Someone in Your Household Has Diphtheria?
Contact a healthcare professional or appropriate public health service as soon as possible.
Close household members may need assessment, preventive antibiotics and a review of their vaccination status. (WHO: Diphtheria Questions and Answers)
Frequently Asked Questions About Diphtheria
Is diphtheria curable?
Diphtheria can be treated. Early treatment commonly involves diphtheria antitoxin and antibiotics and can reduce the risk of severe complications. (WHO: Diphtheria)
Can diphtheria kill?
Yes. Severe disease can cause airway obstruction and toxin-related complications involving the heart and nervous system. (WHO: Diphtheria)
Can adults get diphtheria?
Yes. Diphtheria can affect people of any age who are not adequately protected.
How does diphtheria spread?
It can spread through respiratory droplets, close contact, and contact with infected skin sores or secretions. (WHO: Diphtheria Questions and Answers)
How long after exposure do symptoms appear?
Symptoms usually develop about 2 to 5 days after exposure. (CDC: Diphtheria Symptoms)
Is there a vaccine for diphtheria?
Yes. Diphtheria is a vaccine-preventable disease, and the vaccine is commonly given as part of combination vaccines. (CDC: Diphtheria Vaccination)
Can a vaccinated person get diphtheria?
Vaccination provides strong protection, but protection can decrease over time, which is why recommended doses and boosters' matter. (CDC: Types of Diphtheria Vaccines)
What should I do after exposure?
Seek medical advice promptly. Close contacts may need preventive antibiotics, monitoring and vaccination assessment. (WHO: Diphtheria)
Is diphtheria the same as tonsillitis?
No. Diphtheria is a specific bacterial infection, while tonsillitis can have several causes.
How Diphtheria Fits into Preventive Health
Diphtheria shows why prevention matters: vaccination can reduce the risk of infection, while early recognition helps people access treatment sooner.
For the wider picture, read our article Preventive Health: Definition, Importance, and Ways to Prevent Disease.
You can also explore our article Communicable and Non-Communicable Diseases guide to learn more about infectious diseases and how they spread.
The Bottom Line
Diphtheria is serious, but it is preventable and treatable.
Remember:
Vaccination is the main form of prevention.
A grey or white membrane, significant neck swelling, or difficulty breathing or swallowing can be warning signs.
People who have been exposed may need medical assessment even if they feel well.
Suspected diphtheria requires prompt professional care.
For Nigerian families, keeping routine vaccinations up to date and seeking medical care early when concerning symptoms appear are important steps in reducing the risk of serious disease.
Frequently Asked Questions About Diphtheria
Is diphtheria curable?
Diphtheria can be treated; early treatment usually consists of diphtheria antitoxin and antibiotics and thus helps to reduce the risk of serious complications. (WHO: Diphtheria)
Can diphtheria kill?
Certainly. Severe cases may lead to airway blockage as well as complications caused by toxins affecting the heart and the nervous system. (WHO: Diphtheria)
Can adult people contract diphtheria?
Yes, diphtheria can strike anyone of any age as long as they are not adequately protected.
How does diphtheria spread?
Diphtheria spreads from person to person, usually through coughing or sneezing. Tiny droplets from an infected person can land on someone nearby or on surfaces. If you touch these droplets and then touch your mouth, nose, or eyes, you can get sick. Sharing personal items like cups or eating utensils with someone who has diphtheria can also pass the infection. In rare cases, open sores with diphtheria bacteria can spread the illness through direct contact.
It may be transmitted by respiratory droplets, through close contact, and by touching skin sores or secretions of an infected person. (WHO: Diphtheria Questions and Answers)
When do the symptoms show up after exposure?
The symptoms typically appear about 2 to 5 days following exposure. (CDC: Diphtheria Symptoms)
Is there a vaccine available for diphtheria?
Yes, diphtheria is a disease which can be prevented by means of vaccination, and the vaccine is usually included in combination vaccines. (CDC: Diphtheria Vaccination)
Can a vaccinated person get diphtheria?
Yes, a person who has had the diphtheria vaccine can still get diphtheria, but this is rare. The vaccine is very good at protecting against the disease, but no vaccine works every time. Over time, the protection from the shot can fade. This is why doctors recommend booster shots every 10 years. People who have not had all their shots or whose immunity has worn off are more likely to get sick if they meet the bacteria. Even if a vaccinated person gets diphtheria, their illness is usually milder than it would be without the vaccine.
Vaccination gives strong protection, but this protection may weaken with time, which is the reason why it is important to receive the recommended doses and boosters. (CDC: Types of Diphtheria Vaccines)
What are my next steps after having been exposed?
You should get medical advice as soon as possible; people who have had close contact might be given preventive antibiotics, placed under monitoring, and have their vaccination status assessed. (WHO: Diphtheria)
Is diphtheria the same as tonsillitis?
Diphtheria is a bacterial infection specific to that disease, whereas tonsillitis may have a number of causes.
How Diphtheria Vaccine Fits into Preventive Health
Vaccination can reduce the risk of getting the disease and early recognition enables people to receive treatment more quickly.
If you want to know more about the general topic, see our article on Preventive Health: Definition, Importance, and Ways to Prevent Disease.
You can find out more about infectious diseases and the ways in which they spread by looking at our article Communicable and Non-Communicable Diseases guide.
The Bottom Line
Diphtheria is a serious disease, but it can be prevented and treated.
Remember:
Vaccination is the primary means of prevention.
A grey or white membrane, noticeable swelling in the neck, or trouble with breathing or swallowing may all be warning signs.
Even if people feel okay, those who have been exposed may still need to have a medical evaluation.
Suspected diphtheria must receive immediate professional treatment.
For Nigerian families it is important to keep their routine vaccinations up to date and to seek medical attention as early as possible when any concerning symptoms show themselves.
