Adverse effects of benzalkonium chloride on the nasal mucosa: Allergic rhinitis and rhinitis medicamentosa

Prolonged, repeated use of nasal decongestants for symptomatic relief of al lergic rhinitis often results in rhinitis medicamentosa (RM), a condition i nvolving "rebound swelling" and additional congestion. Most decongestant sp rays contain the preservative benzalkonium chloride (BKC), which causes tox ic reactions in the nose, eyes, ears, and lungs, and may exacerbate the sym ptoms of allergic rhinitis. Recent studies demonstrate the effects of nasal sprays containing BKC or the decongestant oxymetazoline (OXY) in the devel opment of RM. Using rhinostereometry, a technique that measures nasal mucos al swelling and nasal reactivity (with histamine challenge tests), prolonge d use of OXY has been shown to induce nasal mucosal swelling and hyperreact ivity. Sustained use of BKC alone induces nasal mucosal swelling and, in co mbination with OXY, BKC appears to have a long-term adverse effect on nasal mucosa. Its presence may also contribute to the RM resulting from overuse of decongestant sprays. Additional research is needed to confirm the delete rious effects of BKC in nasal products. However, these potential effects ma y be points of clinical differentiation in the treatment of allergic rhinit is and prevention of RM.