Background: Our objective is to present recent research findings on recalcitrant chronic rhinosinusitis (CRS) in relation to "Severe Chronic Upper Airway Disease" (SCUAD).
Methodology: Literature review using Medline and Em base databases (search terms 'chronic rhinosinusitis'; "chronic sinusitis" or"Severe Chronic Upper Airway Disease") limited to articles published in the English language.
Results: Complex pathophysiological mechanisms characterize various forms of chronic rhinitis and rhinosinusitis (CRS), where inflammation persists in spite of adequate medical treatment. In these cases, a multifactorial etiology often underlies the development of sino-nasal inflammation. The interaction between chronic upper and lower airway inflammation via neurogenic and systemic pathways may complicate the therapy of these patients, and lead to insufficient symptom control.
Conclusion: The recently introduced definition of"Severe Chronic Upper Airway Disease" (SCUAD) increases awareness of those patients with persistent inflammation and symptoms despite guideline-driven pharmacologic treatment. The concept of SCUAD may prove helpful in directing research towards clarifying the definition, diagnosis and pathophysiology of rhinitis and rhinosinusitis,their limits and overlap. In this review, a hypothesis on SCUAD immunopathology is also presented.