An illness caused by bacteria infecting the nose and throat or the skin that a vaccine helps prevent.

Diphtheria is caused by bacteria. They can infect the nose and throat, called respiratory diphtheria, or the skin, called cutaneous diphtheria. Untreated diphtheria can lead to organ damage or death, especially in children. A vaccine helps prevent diphtheria.

Respiratory diphtheria symptoms include swollen lymph glands in the neck, sore throat, and fast breathing or a hard time breathing. The infection causes a gray sheet of tissue to form on the tonsils and throat. Skin symptoms of infection include round sores.

Diphtheria is treated with medicine that targets bacteria, called an antibiotic. In respiratory diphtheria, a tube may be placed in the airway. This helps protect the ability to breathe. Another medicine called antitoxin may be used to block toxin made by the bacteria.