My Daughter Started With A Cough And Couldn't Stop Coughing

My daughter started with a cough and couldn't stop coughing which made everything hurt and she lost her voice. She doesn't hurt anymore but the voice is only just returning after nearly four weeks and this happens once a year. Please could you give some advice on this. She went to the doctor who thought it could be bronchitis but reading up on this it doesn't seem so and thankfully it didn't go to pneumonia.