Overview

Diphtheria is a serious bacterial infection caused by Corynebacterium diphtheriae. It primarily affects the mucous membranes of the throat and nose, though it can also infect the skin. The bacteria produce a powerful toxin that can cause severe damage to tissues and organs, leading to life-threatening complications.

While diphtheria is rare in countries with widespread vaccination programs, it remains a concern in regions with low immunization rates. According to the World Health Organization (WHO), fewer than 10,000 cases are reported globally each year, but outbreaks can occur in unvaccinated populations.

The disease most commonly affects children under 5 and adults over 60, particularly those who are unvaccinated or have weakened immune systems. However, anyone can contract diphtheria if exposed to the bacteria.

Symptoms

Diphtheria symptoms typically appear 2 to 5 days after infection. The severity varies depending on the site of infection and whether the toxin has spread through the bloodstream.

Respiratory Diphtheria (Most Common Form)

• Sore throat and hoarseness: Often one of the first signs, accompanied by a mild fever.
• Grayish membrane in the throat: A thick, gray coating (pseudomembrane) forms over the throat and tonsils, which can obstruct breathing.
• Swollen glands (lymph nodes): Noticeable swelling in the neck, sometimes called "bull neck."
• Difficulty breathing or swallowing: Due to the membrane blocking the airway.
• Nasal discharge: May be bloody or contain a grayish membrane if the nose is infected.

Cutaneous (Skin) Diphtheria

• Skin ulcers or sores: Typically painful, with a grayish membrane.
• Redness and swelling: Around the infected area.
• Slow healing: Lesions may persist for weeks.

Systemic Symptoms (If Toxin Spreads)

• Weakness or paralysis: Affecting muscles, including those used for breathing.
• Heart complications: Such as myocarditis (inflammation of the heart muscle).
• Nerve damage: Leading to numbness or tingling in extremities.

Source: Centers for Disease Control and Prevention (CDC)

Causes and Risk Factors

Causes

Diphtheria is caused by the bacterium Corynebacterium diphtheriae. The infection spreads through:

• Respiratory droplets (coughing or sneezing).
• Direct contact with infected skin lesions.
• Contaminated objects (rarely).

The bacteria produce a toxin that damages tissues and can enter the bloodstream, affecting organs like the heart and nerves.

Risk Factors

Certain factors increase the risk of contracting diphtheria:

• Lack of vaccination: Unvaccinated individuals or those who haven’t received booster shots are at highest risk.
• Travel to endemic areas: Regions with low vaccination rates, such as parts of Africa, Asia, and South America.
• Weakened immune system: Due to conditions like HIV/AIDS or chemotherapy.
• Crowded or unsanitary conditions: Increases exposure risk.
• Age: Children under 5 and adults over 60 are more vulnerable.

Source: Mayo Clinic

Diagnosis

Diphtheria is diagnosed through a combination of clinical evaluation and laboratory tests:

• Physical exam: A doctor will check for the characteristic gray membrane in the throat or skin lesions.
• Throat or wound culture: A swab is taken from the infected area and tested for C. diphtheriae.
• Toxin testing: If the bacteria are detected, further tests confirm whether they produce the toxin.
• Blood tests: To assess complications like heart or nerve damage.

Early diagnosis is critical, as delayed treatment increases the risk of severe complications.

Source: National Institutes of Health (NIH)

Treatment Options

Diphtheria requires immediate medical treatment, often in a hospital setting. Treatment includes:

Antitoxin Therapy

The most critical step is administering diphtheria antitoxin to neutralize the toxin in the body. This is given intravenously (IV) and must be started as soon as possible.

Antibiotics

Antibiotics like penicillin or erythromycin are used to kill the bacteria and stop toxin production. A typical course lasts 14 days.

Supportive Care

• Airway management: If breathing is obstructed, a tracheostomy (surgical airway) may be needed.
• Heart monitoring: Due to the risk of myocarditis.
• Isolation: Patients are isolated to prevent spreading the infection.

Follow-Up

After recovery, patients should complete their diphtheria vaccination series to prevent reinfection.

Source: Cleveland Clinic

Living with Diphtheria

Recovery from diphtheria can take weeks, and some complications may require long-term management:

• Rest: Avoid physical exertion, especially if heart complications are present.
• Hydration and nutrition: Soft foods and fluids are recommended if swallowing is difficult.
• Physical therapy: For muscle weakness or paralysis.
• Regular check-ups: To monitor heart and nerve function.

Prevention

The most effective way to prevent diphtheria is vaccination. The diphtheria vaccine is usually combined with tetanus and pertussis (whooping cough) in the DTaP (for children) or Tdap (for adults) vaccine.

Vaccination Schedule

• Infants/Children: 5 doses of DTaP at ages 2, 4, 6, 15–18 months, and 4–6 years.
• Adolescents: A Tdap booster at age 11–12.
• Adults: A Td (tetanus-diphtheria) booster every 10 years, or Tdap if not previously received.

Additional Prevention Tips

• Practice good hygiene (handwashing, covering coughs).
• Avoid close contact with infected individuals.
• Travelers to high-risk areas should ensure vaccinations are up to date.

Source: CDC

Complications

If untreated, diphtheria can lead to severe complications, including:

• Airway obstruction: From the thick membrane, leading to suffocation.
• Myocarditis: Heart muscle inflammation, which can cause heart failure.
• Neuropathy: Nerve damage affecting muscles, including those for breathing.
• Kidney failure: Due to toxin-related damage.
• Death: Diphtheria has a fatality rate of 5–10%, even with treatment, and up to 20% in children under 5.

When to Seek Emergency Care