Diphtheria is an acute infectious disease caused by a toxin from the bacterium Corynebacterium diphtheriae. The most common form of the disease affects the throat and the tonsils. Other forms can cause skin infections. The disease spreads mainly by droplet infection from person to person through the respiratory tract and can affect all age groups, particularly unimmunized children. Overcrowded living conditions contribute to the spread of the disease among family members and may lead to outbreaks. An infected patient, if not treated, can die following complications affecting the heart, central nervous system and respiratory system.

The treatment of diphtheria aims to neutralize the circulating toxin and eliminate the diphtheria bacterium. In order to prevent complications and death, patients with suspected diphtheria should be isolated and treated with antibiotics and diphtheria antitoxin. Antibiotics should also be given to close contacts.