Rhinosinusitis and asthma: epiphenomenon or causal association?

I t has long been recognized that diseases of upper and lower airways may coexist. Indeed, as many as 80% of patients with asthma have rhinitis,1 and up to 15% of patients with allergic rhinitis have asthma.2 Sinusitis and asthma are also frequently associated in the same patient, but doubts still remain as to whether a causal relationship exists wherein sinusitis worsens bronchial asthma, or whether they are manifestations in different parts of the respiratory tract of the same underlying disease process. According to a recent consensus document,3 the term of rhinosinusitis should be preferred in children, because (1) rhinitis and sinusitis in children are often a continuum of the same disease, and (2) it is not possible to differentiate these two conditions on clinical grounds alone. Indeed, there are many similarities in anatomic, physiologic, and pathologic characteristics of the nose and paranasal sinuses. The following definitions are recommended: Acute rhinosinusitis is a sinus infection in which complete resolution of symptoms without intermittent upper respiratory tract infection may take up to 12 weeks. Chronic rhinosinusitis is a sinus infection with low-grade symptoms and signs that persist for longer than 12 weeks, although acute exacerbations can occur in chronic infection. Recurrent acute rhinosinusitis consists of multiple acute episodes in which symptoms and signs resolve completely between episodes. The diagnosis of rhinosinusitis in children is usually made on clinical grounds alone, and imaging studies are not universally necessary in the diagnosis of sinus disease.3 Although sinus radiographs may be misleading in assessing the ethmoid sinuses or the sphenoid and frontal sinuses in small children, they can be helpful in diagnosing maxillary sinusitis in older children.4 CT scans may be required in specific cases, ie, when symptoms persist despite appropriate medical management, when suppurative complications are present, and if endoscopic sinus surgery is being considered. However, because the prevalence of sinus abnormalities in asymptomatic children may be as high as 50%, the interpretation of CT scanning should always be done within the context of history and clinical findings.5