Eosinophil count may predict Allergic-like Rhinitis among patients with chronic rhinosinusitis

Certain parameters like blood eosinophil count and proportion may be good diagnostic predictors of allergic-like rhinitis but cannot differentiate between Allergic rhinitis and non-allergic rhinitis as per a recent study that was published in the journal Clinical Otolaryngology.  

Allergic rhinitis (AR) and nonallergic rhinitis (NAR) are frequently comorbid with chronic rhinosinusitis (CRS). Finding a proper useful test that differentiates these complex conditions is helpful for successful treatment. Hence researchers conducted a study to analyze blood parameter differences between AR and NAR patients with/without CRS. 

A retrospective study was done on eight hundred thirteen patients that included AR and NAR along with different conditions like CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). Healthy controls (HC) included patients with a nasal deviation alone. The value of blood parameters for diagnosing AR or NAR with/without CRS was assessed using the receiver operating characteristic analysis. 

Results

• Compared to nonallergic-like rhinitis (HC, CRSwNP, and CRSsNP), the blood eosinophil count was significantly increased in the allergic-like rhinitis groups, except for NAR-CRSsNP (AR, AR-CRSwNP, AR-CRSsNP, NAR, and NAR-CRSwNP). 
• A higher level of eosinophils than the HC and CRSsNP groups was found in the NAR-CRSsNP.
• Among allergic-like rhinitis patients, eosinophils were higher in allergic-like rhinitis patients with CRSwNP (AR-CRSwNP and NAR-CRSwNP) than in allergic-like rhinitis patients without CRSwNP (AR, AR-CRSsNP, NAR, and NAR-CRSsNP).
• There was no difference in blood eosinophils between AR and NAR.
• The difference was not observed even among nonallergic-like rhinitis patients.
• Blood eosinophil proportion also showed similar findings. 
• The blood eosinophil count was a good predictor of allergic-like rhinitis, especially allergic-like rhinitis with CRSwNP. 

Blood parameters like the eosinophil count and proportion may be good diagnostic predictors of allergic-like rhinitis and are better for predicting allergic-like rhinitis with CRSwNP. But these parameters cannot be used to differentiate between AR and NAR. 

Further reading: Luo Q, Zhou S, Yuan B, Feng Z, Tan G, Liu H. Blood eosinophil count in the diagnosis of allergic-like rhinitis with chronic rhinosinusitis [published online ahead of print, 2022 Oct 12]. Clin Otolaryngol. 2022;10.1111/coa.13990. doi:10.1111/coa.13990