Did the cough start out of nowhere? When my kid gets a dry cough, it's usually because she was sick at some point, had a cough, and then it lingered after her virus cleared up (doctor says this happens when the throat gets irritated).
If it's out of nowhere, yes, I'd see a doctor.
If it's related to a prior virus, we usually do cough drops to soothe her throat and try to get her extra opportunities to rest her throat to help it heal. So less running around screaming with her friends at the park, more quiet activities at home with a lozenge and plenty of fluids, at least for a few days until the cough calms down.