I hear ya!! Teachers are a major reason why students become 'repeat offenders'. I sent a mass staff e-mail (so teachers wouldn't feel cornered) and offered tips. Send the kid for water, have them go to the bathroom, tell them to wait until the end of the lesson (9 times out of 10 they will forget), or for students really pushing the issue ask them what the nurse can do for them. If they can't come up with a legitimate answer, they stay in class. I've also been deemed as a 'not very fun nurse' by some of my repeat offenders. I have a huge stack of books in my office. "School is for strengthening the mind, read a book!" Half a picture book later, they're outa there! Don't get me wrong, I am very sympathetic to those who are sick or just having a really crummy day. Those who need rest, get rest. Those who need to go home, go home. But those who don't like math or want to go home and play XBox (usually they slip and will say something implying they just want to go home), get a lecture. I'm a very busy health room with just the meds I need to give..I don't have time for noncense. I try to scare them away with germs first. Like, "I had a kid in here earlier coughing and sneezing all over the place; do you know how fast germs can spread?!" Girls especially think it's really gross. Or if they say they don't know what's wrong or 'just don't feel good' I reply with, "Oh no! Well what's best here is if you come in on your recess time so that I can watch you..you must just be really sick if you can't figure out what's wrong!" When their own free time is on the line, they tend to rethink things.
You learn fast which kids are ALWAYS coming in and how to control it. Like I said, start with the teachers. Most aren't empathetic at all because it's 'our job' but I keep a list of how many students teachers send in a day. I email the teacher with the info and cc the principal. Worked like a charm with my problem teachers. Now I have a little less BS goin on in my office, and it's pretty nice!