Add Yahoo as a preferred source to see more of our stories on Google. Human mouths contain 700 species of bacteria at all times.Getty Images A man contracted a "flesh-eating" infection, necrotizing ...

Swollen lips may be caused by allergic reactions, injuries, chapping or sunburn, infections, and cysts called mucoceles. The swelling comes from either inflammation or built-up fluid under the skin.

Is that red bump a spider bite or could it be a staph infection caused by methicillin-resistant Staphylococcal aureus (MRSA)? MRSA, a newer type of staph infection, has been present in Iowa since at ...