Effects of systemic immunotherapy on olfactory function in allergic rhinitis patients

Allergic rhinitis (AR), a chronic inflammatory disorder of the nasal mucosa, affects approximately 20% of the world's population and often causes olfactory dysfunction. Conventional treatments cannot cure it, but only alleviate and control the symptoms. Systemic immunotherapy (SIT) is the only curative treatment for AR, but its positive effect on olfactory function has not been quantitatively demonstrated. We measured the olfactory function in patients using a "Sniffin' Sticks" test and analyzed the effects of subcutaneous SIT.

The study included 12 patients (aged 13-44 years) who were eligible to receive subcutaneous SIT to treat AR between 2010 and 2012 in the Department of Otolaryngology, Sisli Etfal Training and Research Hospital. A 3-step Sniffin' Sticks test was performed before and 18 months after subcutaneous SIT. The data collected before and after treatment were compared for each patient.

The average scores for smell test parameters increased after treatment. Although improvements in the mean threshold, mean discrimination, and mean total scores were not significant, the mean identification score was significantly improved after treatment (P < 0.05). Age, sex, and smoking were not significantly related to the changes in the parameters.

Subcutaneous SIT improved the olfactory performance in AR patients. Additional studies with larger patient populations and longer follow-up periods are needed to establish subcutaneous SIT as an effective treatment for olfactory disorders in these patients.