Unveiling the Impact of Smoking on Allergic Rhinitis: Symptom Severity and Long-Term Efficacy of Subcutaneous Immunotherapy

Introduction: Smoking is a considerable negative impact to various diseases. However, its effects on allergic rhinitis (AR) symptoms and subcutaneous immunotherapy (SCIT) efficacy are unclear. This study aimed to assess the impact of different smoking statuses on AR patients' symptoms, and the long-term efficacy of dust mite allergen SCIT.

Methods: A total of 310 AR patients who underwent dust mite allergen SCIT were categorized into three groups: never smokers, former smokers, and current smokers. Symptoms were assessed using widely employed questionnaires for symptom severity and quality of life, including total nasal symptom score (TNSS), symptom and medication score (SMS), rhinoconjunctivitis quality of life questionnaire (RQLQ), and visual analogue score (VAS). Changes in AR symptoms pre and post-SCIT were evaluated for efficacy. Differences in symptoms and SCIT efficacy were compared for different smoking statuses among AR patients.

Results: The former and current smoker groups exhibited a significant increase in male proportion, alcohol, and asthma prevalence compared to never smokers (p < 0.05). Current smokers had a higher prevalence of allergic conjunctivitis and a longer duration of smoking than former smokers (p < 0.05). The symptom severity and quality of life before SCIT did not differ among 3 smoking status groups (p > 0.05). Smoking or smoking cessation did not significantly influence symptom severity across gender, smoking index, or type of sensitization (p > 0.05). After 3 years of SCIT, there were significant reductions in symptom severity and improved quality of life across 3 groups (p < 0.05). But the long-term efficacy of SCIT did not differ among 3 smoking status groups (p >0.05).

Conclusions: Different smoking statuses did not significantly affect either symptoms severity or long-term efficacy of SCIT in AR patients. Active smoking may increase the risk of asthma, while smoking cessation may help reduce the occurrence of allergic conjunctivitis.