Introduction
Antihistamines are among the most prescribed medicines in otorhinolaryngology. This drug, which is excellent for rhinorrhea, sneezing and itching, is often prescribed in combination with upper respiratory infections such as colds and rhinitis. However, all drugs have side effects. Antihistamine has been reported to promote otitis media effusion,1 and antihistamines such as dimetindene and azelastine have been shown to reduce ciliary beat frequency significantly.2 This reduced ciliary beat frequency has been shown to reduce mucociliary clearance, a major defense mechanism in the respiratory mucosa, which ultimately lengthens the time that microorganisms or pollutants can contact nasal mucosa and increases the risk of sinusitis.3 In particular, the reduced ciliary beat frequency is a characteristic of epithelial metaplasia.3 In inflammatory conditions such as sinusitis, not only is the ciliary beat frequency reduced but mucociliary clearance function is decreased due to increased mucus production.4
Nevertheless, there are still many clinicians who prescribe antihistamines to patients with sinusitis.5 This is because the ciliary beat frequency of patients who already have sinusitis does not differ significantly from controls who do not have sinusitis.6 Antihistamine is one of the top three drugs prescribed by Asian pediatricians for the treatment of acute rhinosinusitis.7 There is also a group who think that antihistamine is helpful in rhinosinusitis with allergic rhinitis.8 In some animal studies, it is also reported that desloratadine inhibits allergic symptoms during allergen exposure and reduces the augmented bacterial response.9
Taken together, antihistamine has a debatable effect in rhinosinusitis. At this point, it is useful to examine the relationship between antihistamine and the incidence of sinusitis based on large-cohort data analysis.