Diphtheria
Diphtheria is a vaccine-preventable bacterial disease that can block the throat, damage the heart and nerves, and spread through respiratory droplets or infected skin lesions.
What diphtheria is
Diphtheria is an infection caused by bacteria that can produce diphtheria toxin. The toxin can injure tissue in the throat and spread through the bloodstream to damage the heart, nerves, and kidneys. Vaccination has made diphtheria rare in many countries, but outbreaks still occur when vaccination coverage drops.
How it spreads
Respiratory diphtheria spreads through droplets from coughing or sneezing and through close contact with an infected person. Cutaneous diphtheria affects the skin and can spread through contact with infected wounds or contaminated items. People can carry toxin-producing bacteria even when symptoms are mild.
Symptoms
Respiratory symptoms can include sore throat, low fever, swollen neck glands, weakness, hoarseness, and trouble swallowing. A tough gray-white membrane can form over the tonsils, throat, or nose. Skin diphtheria can cause slow-healing sores or ulcers, especially in crowded settings or where hygiene and health access are limited.
Why the toxin is dangerous
Diphtheria toxin can kill cells near the infection site and trigger the thick membrane that gives respiratory diphtheria its classic appearance. If toxin spreads through the body, it can cause myocarditis, heart rhythm problems, nerve injury, paralysis, kidney problems, or death. Antitoxin works best before toxin has bound deeply to tissues.
Diagnosis
Clinicians consider diphtheria when symptoms, vaccination history, travel, exposure, or local outbreaks fit the pattern. Laboratory testing can culture Corynebacterium species and check whether the bacteria produce toxin. Because severe diphtheria can progress quickly, treatment and public-health action should not wait for every test result.
Treatment
Treatment can include diphtheria antitoxin to neutralize circulating toxin, antibiotics to kill the bacteria, airway support if breathing is threatened, isolation to prevent spread, and monitoring for heart or neurologic complications. Close contacts may need evaluation, antibiotics, testing, and vaccination updates.
Vaccination
Diphtheria vaccines use an inactivated toxin, called toxoid, to train the immune system. They are usually combined with tetanus and pertussis components in vaccines such as DTaP, Tdap, Td, or other national schedule products. Boosters matter because protection can decline over time.
Why it matters
Diphtheria shows how fast a controlled disease can return when routine immunization weakens. It is also a disease of systems: early recognition, antitoxin access, laboratory confirmation, contact tracing, isolation, antibiotics, and vaccine catch-up all need to work together.
What public health teams watch
Public-health teams monitor suspected cases, lab confirmation, toxin testing, vaccination coverage, close contacts, school or community clusters, and antitoxin supply. Outbreak response can include case isolation, contact prophylaxis, targeted vaccination, and clear risk communication.