How to handle personal hygiene can be a sensitive subject for students. It is hard to immediately know what to do when this matter comes up. A student may seem embarrassed, and parents may be offended. However, it needs to be addressed. Ignoring it was my first instinct. But upon occurrences on multiple occasions it is an issue. Not only may other students be teasing, because I remember it happening in my class when I was in elementary school, but it can also negatively effect the close attention situations from the teacher.
A few solutions that I have looked into are holding a whole class lesson on personal hygiene. No student should feel pointed out, and students hopefully wont know who it is about either. Anther option is talking to the parents or students, both while being mindful of what to say.