Global travelers should think twice before grabbing the in-room hair dryer; experts warn the appliance can harbor bacteria and fungi—here's what to do instead.

NEW YORK — Seasoned jet-setters leaving New York for points around the globe already know to stash sanitizing wipes in their carry-ons, but few consider the germs that may be hiding in a hotel’s most innocuous amenity: the hair dryer. The compact device hanging in the bathroom—or wrapped inside the closet safe—can look spotless, yet hair-health specialists say it could be the dirtiest object in the room.