Diphtheria bacteria live in the mouth, nose, throat, or skin of infected persons. Diphtheria spreads from person to person very easily. People get diphtheria by breathing in diphtheria bacteria after an infected person has coughed or sneezed. People also get diphtheria from close contact with discharges from an infected person's mouth, nose, throat, or skin. Usually, diphtheria develops in the throat.
Early symptoms are a sore throat and mild fever.
A membrane that forms over the throat and tonsils can make it hard to swallow. The infection also causes the lymph glands and tissue on both sides of the neck to swell to an unusually large size. Some people can be infected but not appear ill. They can also spread the infection. Symptoms usually appear 2 to 4 days after infection.