Topical corticosteroids potentiate mucin secretion in the normal nose

The exact mode of action of topical nasal corticosteroids is still uncertain. The aim of this study was to determine their effects on microvascular permeability and cellular and glandular secretion by measuring the levels of total protein, albumin, lysozyme and mucin recovered in nasal lavage fluid before and after 3 weeks of treatment with a topical nasal corticosteroid in 12 normal non-atopic subjects. Six subjects applied 200 micrograms fluticasone propionate and six applied 200 micrograms beclomethasone dipropionate to one nostril in each 24 h: matched placebo was applied to the other nostril. There was a significant rise in the level of mucin recovered compared with baseline values following fluticasone administration (baseline 76.2 micrograms/ml (mean) +/- 5.5 (SEM), fluticasone 118.3 micrograms/ml +/- 11.6 P = 0.015) and beclomethasone administration (baseline 64.3 micrograms/ml +/- 6.6, beclomethasone 87.2 micrograms/ml +/- 4.8, P = 0.041). There was no significant change in the levels of total protein, albumin or lysozyme following either active medication or placebo treatment. Topical corticosteroids appear to potentiate mucin secretion and do not alter serous secretion or microvascular permeability in the unchallenged non-atopic nose.