What Causes Persistent Cough In A Child?

My 4 yr old daughter has had a cough for 10 days that has become constant in the couple of days...never stops coughing. It is a bark like cough and does not produce any phlem. It is preventing her from sleeping and when I touch her neck it is very hot and feels like it is spasming. She has taken some Rx robittussen but it s not helping...took 3 1/2 hours ago. Do I need to take her to the ER or r we ok to wait to go to dr in the morning?