This is just a little idea.  When I have an e-mail from a parent telling me that a child is ill, I always reply with a message to the child.  For example, I might say:

Dear Suzy,
I am so sorry to hear that you are sick today.  We will miss you so much!  Please rest so that you can get better and come back to KM.  God bless you.
Love, Mrs. Merritt

It takes maybe two minutes max and engenders a lot of goodwill with students and parents alike.
Kathy