No, it doesn't "mean they have a health issue", and I didn't say that it did. Part of the teacher's job is to look for signs of abuse, bullying, and health problems. I'm not a doctor. I see a possible symptom, I'll bring it to the attention of people who can help. If they are using the bathroom frequently because they are being bullied then I am exactly doing my job in the best way possible by alerting the nurse, who can alert the counselor, etc.