Intranasal corticosteroids for nasal polyposis : biological rationale, efficacy, and safety.

Abstract

Nasal polyposis, occurring in about 2% of the general population, is the ultimate form of inflammation of the upper airways. For unknown reasons, polyps develop preferentially in subtypes of inflammatory diseases and are associated with perennial non-allergic rhinitis, asthma, intolerance of aspirin (acetylsalicylic acid)/NSAIDs, allergic fungal rhinosinusitis, cystic fibrosis, and primary ciliary dyskinesia. In contrast to common beliefs, IgE-mediated allergy does not seem to play an etiological role in nasal polyposis.The polyps originate from the mucosa around the clefts of the lateral nasal wall, especially in the region of the ostiomeatal complex. The factors that determine the localization of the disease to a few square centimeters of the airways are not known.Polyps are edematous bags covered by respiratory epithelium and contain very few nerves, blood vessels, and glands that have undergone cystic degeneration. They contain degranulated mast cells, have a very high concentration of histamine, and are characteristically infiltrated by eosinophils. These cells accumulate due to the release of proinflammatory cytokines (in particular, interleukin-5).Nasal polyposis is preceded by a prolonged history of rhinitis accompanied by severe and persistent nasal blockage; typically, the sense of smell is seriously impaired when polyps develop. The diagnosis is based on anterior rhinoscopy or, preferably, endoscopy.Nasal polyposis is medically treatable. Surgical treatment is carried out when medication fails. Intranasal corticosteroids reduce rhinitis symptoms, improve nasal breathing, reduce the size of polyps, and prevent, in part, their recurrence, but this treatment has little effect on the sense of smell. Intranasal corticosteroids can, as basic long-term therapy, be used alone in mild cases or together with systemic corticosteroids and/or surgery in severe cases. Systemic corticosteroids administered for 2-3 weeks have a beneficial effect on all observed symptoms and pathology, including the sense of smell. When nasal blockage is a problem in spite of medical treatment, surgery is recommended. Simple polypectomy can be performed, but endoscopic surgery is recommended in more severe and persistent cases.