The nasal secretions of allergic rhinitis patients contain substances (mediators) that cause inflammation. These mediators are produced by inflammatory cells reaching the mucosa. These are:
Inflammatory cells are attracted to the mucosa by the allergic process, accumulate there and release mediators. These products have a negative effect on the cells that cover the mucosa (the nasal epithelium), altering them and reinforcing the inflammation.
Nasal irrigation has an anti-inflammatory effect because, as the mucosa is cleansed, it releases mediators and inflammatory cells. This action is supplementary to that of the anti-inflammatory drugs of nasal sprays (corticoids) as these act on the attraction mechanisms, diminishing the arrival of inflammatory cells to the mucosa.