Antibiotics may not be required once the pus has been evacuated unless the infection has progressed into the skin around the site. Depending on the extent of the abscess, the wound will take 1 to 2 weeks to heal. In rare cases, antibiotics are needed for longer than two weeks. This depends on how many different types of bacteria are found inside the lesion and whether any of these organisms are resistant to antibiotics. If this happens, follow all of the instructions given to you by your doctor. You should also keep the site clean and dry, and apply antibiotic ointment if available. The pain should start to subside within a few days or weeks. Cysts can occur at any time during one's life but most often show up between ages 10 and 20. Males and females are affected about equally by the disease. Cysts may sometimes grow back after they have been removed. Sometimes multiple cysts will merge together. This is called "fistulization." Fistulas are holes that connect tissues inside the body, such as organs, bones, muscles, blood vessels, or lymph nodes. Fistulas can be caused by injuries or medical conditions such as tuberculosis, diabetes, cancer, and inflammation. The treatment of choice for simple renal cysts is complete removal.