Effect of Average Relative Humidity on Epistaxis

Background Epistaxis is a very common symptom. The occurrence of epistaxis may be affected by dry environments, but there are some differences among previous reports and this view is controversial. Objective We investigated the relationship between the number of epistaxes and daily average relative humidity. Methods Data on patients with epistaxis between March 2011 and February 2021 were collected from two hospitals. The daily average relative humidity was examined, and the change in the number of patients with epistaxis due to humidity was investigated using a generalized linear mixed model. Results A total of 4184 cases of epistaxis were identified. The number of epistaxis cases per day was significantly associated with the daily average relative humidity (p < 0.001). One percent increment in average relative humidity decreases the number of epistaxis cases per day by 1.1%. Conclusion A negative correlation was found to exist between daily average relative humidity and occurrences of epistaxis.