Paranasal sinusitis after long-term use of topical nasal decongestants

The aim of this study was to evaluate the incidence of paranasal sinusitis and the histologic changes in the sinus mucosa after long-term administration of topical nasal decongestants, phenylephrine and oxymetazoline. Experimental animals were divided into 3 groups for topical administration for 1 week, 2 weeks, and 4 weeks. Purulent maxillary sinusitis developed in 4 of 10 two-week phenylephrine group, 6 of 10 four-week phenylephrine group, 1 of 10 two-week oxymetazoline group and 3 of 10 four-week oxymetazoline group. Administration of phenylephrine and oxymetazoline for more than 2 weeks caused histologic changes in the maxillary mucosa of the rabbits. Light microscopy showed ciliary loss, epithelial ulceration, inflammatory cell infiltration and edema. The histologic changes were more pronounced with increasing duration of administration of the decongestants. Ciliary loss was more prominent in the 4-week phenylephrine group than in the oxymetazoline group. Dilatation of mitochondria and vacuolization in cytoplasm were prominent in the 4-week groups with both phenylephrine and oxymetazoline. The results of this study suggest that the administration of decongestants may cause ciliary loss with subsequent sinusitis.