An endscopic imaging device is described that achieves longitudinal axis (z-axis) scanning into a tissue or sample, using a piezoelectric microactuator. In some configurations, additional lateral (xy-plane) scanning is also achieved, to allow for the creation of full three-dimensional imaging, ex vivo or in vivo. The techniques may be used to image and diagnosis allergic rhinitis and eosinophilic esophagitis in tissue.