Rhinitis medicamentosa: electron microscopic study.

The deleterious effect of decongestant drops on the rabbit respiratory nasal mucosa was studied with the aid of the electron microscope. The cilia were severely damaged, with the appearance of virus-like particles. The epithelium showed characteristic morphological details suggestive of oedematous infiltration. The tunical blood vessels revealed ultrastructural changes of their endothelial lining and basal lamina indicative of increased permeability.