From Bench to Bedside: Allergic Rhinitis
Since allergic rhinitis is a chronic inflammatory disease, topical intranasal steroids have become first line therapy for relief of nasal discomfort. Their benefit is primarily due to anti-inflammatory effects, such as the inhibition of migration of leukocytes into tissue (chemotaxis). They are also thought to inhibit mucus secretion seen in allergic rhinitis by their action on mucin-producing cells in the nasal mucosa.
Biopsies have shown that steroids sprayed in the nose (but not oral steroids), decrease the number of mast cells in the mucosa and have been shown to inhibit both the early and late phases of the Type I hypersensitivity reaction. This is in contrast to antihistamines, which for the most part, only inhibit the histamine-mediated effects of the early phase. Intranasal steroids have clearly been shown to diminish sneezing, rhinorrhea, and nasal stuffiness after nasal allergen challenge in the sensitized individual. In clinical trials they have not only been shown to be efficacious, but also to have excellent safety profiles.
Adverse reactions from nasal steroids are relatively rare and usually limited to mild epistaxis and occasional local irritation - the latter can sometimes be circumvented by the use of aqueous preparations. Hypothalamic-pituitary-adrenal suppression is not usually seen with doses of inhaled steroid less than 1000 mcg per day, so it is rarely seen in intranasal use (doses for allergic rhinitis rarely exceed 400 mcg/day).
Intranasal steroids in sinus and eustachian tube disorders
Because of their anti-inflammatory effect on the nasal mucosa, nasal steroids may decrease swelling around the eustachian tube orifices and sinus ostia. Therefore, intranasal steroids should be considered an additional tool to help reduce the number of infections in children and adults with recurrent otitis and/or sinusitis. To date there have been no adequate clinical studies to address the potential benefit of these medications for such patients with recurrent infections - though many clinicians have found them to be an effective alternative to prophylactic antibiotics or surgical intervention.