Per CDC:
Diphtheria is a name for any illness caused by a toxin produced by some strains of C. diphtheriae. Diphtheria toxin, rather than C. diphtheriae, is responsible for the serious effects of diphtheria. The toxin kills healthy tissues and can cause many serious health problems.
Types
Respiratory diphtheria
The most common and serious type of diphtheria occurs when toxin-producing C. diphtheriae infect the upper respiratory tract (nose, throat). When this happens, it's called respiratory diphtheria.
Skin infections
C. diphtheriae can also infect the skin and other body parts. Cutaneous (skin infection) diphtheria is when bacteria that make diphtheria toxin infect the skin.
How it spreads
People most commonly spread C. diphtheriae by coughing or sneezing, which creates small respiratory droplets that contain the bacteria. Other people can get infected if they breathe in those droplets.
People can also get infected from touching open sores or ulcers caused by C. diphtheriae.
To learn more visit: About Diphtheria | Diphtheria | CDC
