In this Article

• What is diphtheria?
• What is the history of diphtheria?
• What causes diphtheria?
• How is diphtheria transmitted?
• What are the signs and symptoms of diphtheria?
• How is diphtheria diagnosed?
• What is the treatment for diphtheria?
• What are the complications of diphtheria?
• How is diphtheria prevented?
• Diphtheria At A Glance
• Diphtheria Glossary
• Diphtheria Index

How is diphtheria transmitted?

Diphtheria is transmitted to close contacts via airborne respiratory droplets or by direct contact with nasopharyngeal secretions or skin lesions. Rarely, it can be spread by objects contaminated by an infected person. Overcrowding and poor living conditions can further contribute to the spread of diphtheria.

Humans are the only known reservoir of Corynebacterium diphtheriae. Infected individuals may develop symptoms of diphtheria, or they may become carriers of the bacteria with no symptoms (asymptomatic carriers). These asymptomatic carriers can serve as reservoirs for active infection and may transmit the disease to other individuals.

What are the signs and symptoms of diphtheria?

The symptoms of respiratory diphtheria usually begin after a two- to five-day incubation period. Symptoms of respiratory diphtheria may include the following:

• sore throat,
• fever,
• malaise,
• hoarseness,
• difficulty swallowing, or
• difficulty breathing.

With the progression of respiratory diphtheria, the infected individual may also develop an adherent gray membrane (pseudomembrane) forming over the lining tissues of the tonsils and/or nasopharynx. Individuals with severe disease may also develop neck swelling and enlarged neck lymph nodes, leading to a "bull-neck" appearance. Extension of the pseudomembrane into the larynx and trachea can lead to obstruction of the airway with subsequent suffocation and death.

The dissemination of diphtheria toxin can also lead to systemic disease, causing complications such as inflammation of the heart (myocarditis) and neurologic problems such as paralysis of the soft palate, vision problems, and muscle weakness.

Cutaneous diphtheria is characterized by a non-healing skin ulcer covered by a gray-brown membrane. It is typically a localized infection that is rarely associated with systemic complications.