Home Medical Topics Diphtheria – Symptoms, Causes, Diagnosis & Treatment

Diphtheria – Symptoms, Causes, Diagnosis & Treatment


Diphtheria is an acute pharyngeal or cutaneous infection caused mainly by toxigenic strains of the gram-positive bacillusCorynebacterium diphtheriae and rarely by other, less common Corynebacterium species. Non-specific skin infections or pseudomembranous pharyngitis are the symptoms, which are followed by exotoxin-related cardiac and neurological tissue damage. There is also the asymptomatic carrier status. The diagnosis is made clinically, and culture confirms it. Antitoxin and penicillin or erythromycin are used as treatments. Booster shots and vaccinations for children should be commonplace.

Diphtheria toxin

Beta-phage-infected diphtheria strains that have a toxin-encoding gene generate a strong toxin. The heart, nerves, and even the kidneys can be harmed by this toxin when it first causes local tissues to swell and die.

C. diphtheriae nontoxigenic strains can potentially induce nasopharyngitis and, in certain cases, systemic illness (eg, endocarditis, septic arthritis).

Epidemiology and transmission

Humans are the only known reservoir for C. diphtheriae. The organism is spread by

  • Respiratory droplets
  • Contact with nasopharyngeal secretions (including from asymptomatic carriers)
  • Contact with infected skin lesions
  • Fomites (rare)

Unlike wealthy nations, endemic regions frequently have a carrier state. Although the majority of patients who get sufficient treatment do not become carriers, immunity acquired by immunization or active infection may not prevent people from becoming carriers. Individuals who are clinically unwell or carriers who have no symptoms may spread the virus.

The spread of cutaneous diphtheria is facilitated by poor personal and public hygiene.

Due to widespread childhood vaccination, diphtheria is now uncommon in the US and other industrialized nations. Yet with the dissolution of the former Soviet Union, vaccination rates in its member states declined, which was followed by a sharp increase in diphtheria cases. The decline in adult booster vaccination rates has also led to a rise in susceptibility in affluent nations.

Diphtheria is endemic in many countries in Asia, the South Pacific, the Middle East, Eastern Europe, Venezuela, Haiti, and the Dominican Republic. Outbreaks in Indonesia, Thailand, Vietnam, Laos, South Africa, Sudan, and Pakistan have occurred since 2011 (travel information about diphtheria is available at the Centers for Disease Control and Prevention [CDC] web site for travelers’ health). Diphtheria may be present in returning travelers or migrants from countries where diphtheria is endemic.


Diphtheria signs and symptoms usually begin 2 to 5 days after a person becomes infected. Signs and symptoms may include:

  • A thick, gray membrane covering the throat and tonsils
  • A sore throat and hoarseness
  • Swollen glands (enlarged lymph nodes) in the neck
  • Difficulty breathing or rapid breathing
  • Nasal discharge
  • Fever and chills
  • Tiredness

In some people, infection with diphtheria-causing bacteria causes only a mild illness — or no obvious signs and symptoms at all. Infected people who stay unaware of their illness are known as carriers of diphtheria. They’re called carriers because they can spread the infection without being sick themselves.

Skin (cutaneous) diphtheria

A second type of diphtheria can affect the skin, causing pain, redness and swelling similar to other bacterial skin infections. Ulcers covered by a gray membrane also may be a sign of skin diphtheria.

Although it’s more common in tropical climates, diphtheria on the skin also occurs in the United States. It may happen especially among people with poor hygiene who live in crowded conditions.


Diphtheria is caused by the bacterium Corynebacterium diphtheriae. The bacterium usually multiplies on or near the surface of the throat or skin. C. diphtheriae spreads through:

Airborne droplets. When an infected person’s sneeze or cough releases a mist of contaminated droplets, people nearby may inhale C. diphtheriae. Diphtheria spreads easily this way, especially in crowded conditions.
Contaminated personal or household items. People sometimes catch diphtheria from handling an infected person’s things, such as used tissues or hand towels, that may be contaminated with the bacteria.

Touching an infected wound also can transfer diphtheria-causing bacteria.

People who have been infected by the diphtheria bacteria and who haven’t been treated can infect people who haven’t had the diphtheria vaccine — even if they don’t show any symptoms.

Risk factors

People who are at increased risk of catching diphtheria include:

  • Children and adults who don’t have up-to-date vaccinations
  • People living in crowded or unsanitary conditions
  • Anyone who travels to an area where diphtheria infections are more common

In the United States and Western Europe, where children have been immunized against the disease for decades, diphtheria is an uncommon occurrence. Nonetheless, diphtheria is still widespread in underdeveloped nations with poor immunization rates.

If diphtheria immunization is required, those who travel overseas or come into touch with persons from less developed nations and are either unvaccinated or insufficiently vaccinated are most at risk.


Left untreated, diphtheria can lead to:

  • Breathing problems.A toxin may be produced by bacteria that cause diphtheria. This toxin causes tissue damage in the infection’s immediate vicinity, often the nose and throat. An unyielding, gray membrane composed of bacteria, dead cells, and other elements develops at that location as a result of the infection. This membrane may prevent airflow..
  • Heart damage. The diphtheria toxin has the potential to circulate throughout the body and harm various tissues. For instance, it may harm the heart muscle, resulting in consequences such heart muscle inflammation (myocarditis). Myocarditis may cause minor or serious heart damage. Myocarditis can, at its worst, cause heart failure and unexpected death.
  • Nerve damage. The toxin can also cause nerve damage. Typical targets are nerves to the throat, where poor nerve conduction may cause difficulty swallowing. Nerves to the arms and legs also may become inflamed, causing muscle weakness.If the diphtheria toxin damages the nerves that help control muscles used in breathing, these muscles may become paralyzed. At that point, you might need mechanical assistance to breathe.

With treatment, most people with diphtheria survive these complications, but recovery is often slow. Diphtheria is fatal about 5% to 10% of the time. Rates of death are higher in children under age 5 or adults older than age 40.


  • Gram stain and culture

Pharyngeal diphtheria needs to be considered in patients with nonspecific findings of pharyngitis, cervical adenopathy, and low-grade fever if they also have systemic toxicity plus hoarseness, palatal paralysis, or stridor. The appearance of the characteristic membrane suggests the diagnosis.

Gram-positive bacteria with metachromatic (beaded) staining and characteristic Chinese-character arrangement, as well as club-shaped swelling at one or both ends, may be seen on the membrane. Either material from below the membrane or a piece of the membrane itself should be sent for cultivation. When C. diphtheriae is detected, the laboratory should be alerted so that specific culture medium (Loeffler or Tindale) can be utilized. To distinguish between toxigenic and nontoxigenic strains, in vitro testing for toxin generation (modified Elek test) is performed. It is possible to do polymerase chain reaction testing for the diphtheria toxin gene.

When a patient experiences skin lesions during an epidemic of respiratory diphtheria, cutaneous diphtheria should be taken into account. Samples from swabs or biopsies have to be cultured. Staphylococcus aureus or group A streptococci may also be co-infected with cutaneous diphtheria lesions.

An ECG should be performed to check for myocarditis-related ST-T wave abnormalities, QTc prolongation, and/or 1st-degree heart block, which frequently manifests as the respiratory symptoms go away.


Diphtheria is a serious illness. Doctors treat it immediately and aggressively. Doctors first ensure that the airway isn’t blocked or reduced. In some cases, they may need to place a breathing tube in the throat to keep the airway open until the airway is less inflamed. Treatments include:

  • Antibiotics. Antibiotics, such as penicillin or erythromycin, help kill bacteria in the body, clearing up infections. Antibiotics lessen the time that someone with diphtheria is contagious.
  • An antitoxin. If a doctor suspects diphtheria, he or she will request a medication that counteracts the diphtheria toxin in the body. This medication comes from the Centers for Disease Control and Prevention. Called an antitoxin, this drug is injected into a vein or muscle.Before giving an antitoxin, doctors may perform skin allergy tests. These are done to make sure that the infected person doesn’t have an allergy to the antitoxin. If someone has an allergy, the doctor will likely recommend that he or she not get the antitoxin.

Children and adults who have diphtheria often need to be in the hospital for treatment. They may be isolated in an intensive care unit because diphtheria can spread easily to anyone not vaccinated against the disease.

Preventative measures

See a doctor for testing and potential treatment if you’ve been around someone who has diphtheria. In order to assist you from contracting the illness, your doctor could provide you an antibiotic prescription. Moreover, you could require a booster dose of the diphtheria vaccination.

Antibiotics are administered to those who have been identified as diphtheria carriers in order to rid their bodies of the germs.


Before the development of medicines, diphtheria was a frequent disease in young children. Now, a vaccination makes the illness not only curable but also prevented.

The diphtheria vaccination is often given in combination with the tetanus and whooping cough vaccines (pertussis). The diphtheria, tetanus, and pertussis vaccination is a three-in-one vaccine. For children, the most recent iteration of this vaccination is known as the DTaP vaccine, while for teenagers and adults, it is known as the Tdap vaccine.

The diphtheria, tetanus and pertussis vaccine is one of the childhood vaccinations that doctors in the United States recommend during infancy. Vaccination consists of a series of five shots, typically administered in the arm or thigh, given to children at these ages:

  • 2 months
  • 4 months
  • 6 months
  • 15 to 18 months
  • 4 to 6 years

Diphtheria can be avoided with the diphtheria vaccination. Nonetheless, there can be some adverse consequences. After receiving a DTaP shot, some kids may suffer a minor temperature, fussiness, tiredness, or pain at the injection site. What can you do for your kid to lessen or relieve these effects? Consult your doctor.

Rarely do complications occur. Rarely, the DTaP vaccination might result in significant but manageable side effects in a kid, such an allergic response (hives or a rash develops within minutes of the injection).

Certain kids, such as those who have epilepsy or another disorder of the neurological system, might not be able to get the DTaP vaccination.

Booster shots

To help you retain your immunity after the original set of childhood immunizations, you need booster doses of the diphtheria vaccine. This is due to the fading of immunity to diphtheria over time.

The first booster shot for kids who had all of the required shots before turning seven should be given at age 11 or 12. It is advised to repeat the booster shot 10 years later and then every 10 years after that. If you go somewhere where diphtheria is prevalent, booster injections are especially crucial.

The Tdap vaccination or the tetanus-diphtheria (Td) vaccine, which combines the diphtheria and tetanus boosters, is administered as the booster. This combination vaccination is administered intravenously, often into the thigh or arm.

For adults who have not had a Tdap booster shot and teenagers aged 11 to 18 there is an alternative vaccination called Tdap. In addition, it is advised just once when pregnant, regardless of prior vaccines.

If you’re unclear about your immunization status, talk to your doctor about vaccinations and booster doses. For children aged 7 to 10 who have not completed the Td series of vaccines, a Tdap vaccination may also be advised.

Lifestyle and home remedies

Diphtheria recovery calls for a lot of bed rest. It’s crucial to refrain from physical activity if your heart has been impacted. Due to pain and difficulties swallowing, you might need to acquire your nourishment through liquids and soft meals for a period.

While you’re sick, you should stay in complete isolation to help stop the virus from spreading. Everyone in your family has to wash their hands thoroughly in order to prevent the infection from spreading.

To avoid a recurrence of diphtheria after recovery, you must receive the complete course of the vaccination. Being infected with diphtheria does not provide permanent immunity, unlike certain other illnesses. If you are not completely protected against it, you can contract it more than once.

You may also like