If your 4-year-old daughter has had a cough that comes and goes for about 3 weeks, it may be a good idea to consult a doctor. Especially if there has been no fever and her general condition is good, it is important to address the persistent cough to ensure it is not a sign of a more serious underlying issue. Consulting a healthcare professional can provide guidance on the best course of action to manage her symptoms and improve her overall health.