Effect of topical glucocorticoid treatment on nasal mucosal mast cells in allergic rhinitis.

Glucocorticoids were previously considered not to affect the immediate allergic reaction. However, in a nasal allergen challenge, an inhibitory effect on the nasal symptoms induced at the challenge has been shown to occur in patients treated with a recently developed glucocorticoid, budesonide, for 1 week prior to the challenge. This treatment was also found to reduce tissue histamine levels in the nasal mucosa. Mast cells in the mucosa were therefore studied with a view to finding out whether this reduction could be due to a reduction of mast cells. A double-blind study was performed in 14 asymptomatic patients. Nasal biopsies were made before and after 1 week's treatment with either budesonide or placebo. The number of mast cells was counted in two Epon sections after the specimens had undergone specific staining with toluidine blue. No quantitative or qualitative morphological changes in the mast cells were found as a result of treatment.