Khloe Kardashian is recovering from a staph infection that she’s believed to have picked up while in the hospital with her estranged husband, Lamar Odom. Khloe was forced to cancel part of her book tour due to the infection.

According to TMZ, Khloe developed a lesion on her leg that became painful. She also has had a high fever and swollen glands and has been sweating profusely.

But what is a staph infection exactly?

It’s a generic term for an infection that occurs with the Staphylococcus bacteria, says board-certified infectious disease specialist Amesh A. Adalja, M.D., an assistant professor at the University of Pittsburgh Medical Center. “It’s a common bacteria that lives on people’s skin.”

While staph can live on your skin and not bother you, you can become infected with staph through a break in your skin, like a cut or sore. It can then create a skin lesion but can also infect your blood and spread throughout the body. “It’s not fun to have, no matter where the infection is,” says Adalja.

Staph infections are usually treated with antibiotics, but how much and how long it will take to recover varies depending on where the infection is and how serious it is. (If it ends up in your heart, for example, we’re talking a months-long recovery; if it’s just in your skin, it’s probably a matter of weeks.) However, Adalja points out that Khloe is probably doing okay since she’s been tweeting a lot lately.