Human bite infections are potentially serious infections caused by rapid growth of bacteria in broken skin.

Bites—animal and human—are responsible for about 1% of visits to emergency rooms. Bite injuries are more common during the summer months.

In adults, the most common form of human bite is the closed-fist injury, sometimes called the "fight bite." These injuries result from the breaking of the skin over the knuckle joint when a person's fist strikes someone's teeth during a fight.

In children, bite infections result either from accidents during play or from fighting. Most infected bites in adults result from fighting.

The infection itself can be caused by a number of bacteria that live in the human mouth. These include streptococci and staphylococci. Infections that begin less than 24 hours after the injury are usually produced by a mixture of organisms and can cause...