Coop and the cause

My daughter, who is almost 6, was just diagnosed with the coop.  What causes this?  She did not have a cold prior to this.  Is it highly contagious?  She has never had this before.  She is being treated with a 2-day liquid steroid and ibuprofen for her fever.

[National Jewish]

Croup is a very common illness of childhood.  It is from a virus and may last several days.  Usually, it is easily controlled and goes away on its own.  Antibiotics have little effect on it.  As with many childhood illnesses, it is very contagious during the first few days of the cough.

[bactitech]

I believe you mean croup.