Does serum leptin levels differ between patients with rhinitis of allergic versus nonallergic aetiology?

Leptin may play a critical role in airway inflammation. However, it has rarely been evaluated in rhinitis with different aetiology. This study aimed to compare the serum leptin levels between allergic rhinitis (AR) and nonallergic rhinitis (NAR).

Patients with chronic rhinitis were classified due to skin prick (ALK-Abello/Madrid) and/or serum-specific immunoglobulin E tests (UniCAP 100-Pharmacia), against to aeroallergens if concordant with symptoms.

A total of 398 patients with a mean age of 29.03 years were recruited and grouped as AR and NAR. Mean serum leptin levels were similar in patients with NAR and AR, as well as in patients with and without asthma, but were significantly higher in females than males in both groups. Also, leptin levels were significantly higher in obese than nonobese patients in AR. In correlation analysis, leptin levels were found to be correlated with female gender, older age, and high body mass index (BMI) in the whole group. Despite the higher total nasal symptom score (TNSS) in patients with AR compared with NAR, there was no association of leptin levels with TNSS, severity and seasonality of symptoms, and allergen sensitization. In logistic regression analysis, younger age and high serum leptin levels were found to be independent predictors for the diagnosis of AR.

We conclude that female patients with high BMI are more prone to AR probably due to immunological effects of adipose tissue, in addition to hormonal factors. This study showed that leptin measurement has limited value as a sole diagnostic tool to differentiate AR and NAR.