The nasal cycle: a comprehensive review

Background: The nasal cycle is the spontaneous, reciprocal congestion and decongestion of the nasal mucosa during the day and it is present in almost 70-80% of healthy adults. The German physician Richard Kayser first described it in 1895. Since then, the number of papers focused on this fascinating issue has continued to flourish. Main body: Even though there are a high number of publications on this topic, the understanding of nasal cycle is still very poor. The present review tries to offer a comprehensive analysis of this issue investigating all the physiologic and pathologic conditions able to modify the nasal cycle. A section of methods used for its evaluation has been also included in this review. Conclusion: The influence of the nasal cycle on nasal airflow must be considered during any rhinologic evaluation, especially if investigating the need for septal/turbinates surgery, rather than nasal medical therapy alone. The nasal cycle is a normal phenomenon and must be recognized in order to differentiate it from the pathologic causes of nasal obstruction.