Deep neck infection (DNI) is a potentially life-threatening bacterial infection that affects the anatomical spaces within the neck, with upper airway infections being among the most common etiological factors. Smoking has well-documented local and systemic effects on the respiratory tract, immune system, as well as on the skin and soft tissues. However, the relationship between smoking and the development of DNI remains inadequately addressed in the existing literature. The objective of this study is to investigate the potential association between smoking and the occurrence of DNI.

A total of 332 patients diagnosed with DNI were enrolled in this study. Of these, 81 patients were identified as smokers, while 251 were non-smokers. A comprehensive analysis of relevant clinical data was conducted to assess the potential association between smoking status and clinical outcomes in this cohort.

In the univariate analysis, age ≥ 60 years (OR = 3.5161, 95 % CI: 1.0481–11.792, p = 0.0293), elevated C-reactive protein (CRP) levels ≥300 mg/L (OR = 3.9375, 95 % CI: 1.1958–12.965, p = 0.0263), and the involvement of multiple anatomical spaces (≥ 3) (OR = 5.8776, 95 % CI: 1.9446–17.764, p = 0.0012) were identified as statistically significant risk factors for prolonged hospitalization (>14 days) in patients with DNI who were smokers. Upon conducting multivariate analysis, it was found that the involvement of multiple spaces (≥ 3) (OR = 3.7383, 95 % CI: 1.1332–12.331, p = 0.0304) emerged as an independent and significant predictor of prolonged hospitalization in this cohort of smokers. However, no statistically significant differences were observed between the groups in terms of the extent of space involvement, the spectrum of pathogens, or the incidence of complications.

This study explored the potential association between smoking and the development of DNI. The findings demonstrated that advanced age, elevated CRP levels, and the involvement of multiple deep neck spaces were significant risk factors for prolonged hospitalization. Multivariate analysis further identified the involvement of three or more deep neck spaces as an independent predictor of extended hospital stay among smokers. Collectively, these results suggest that smokers with DNI exhibit a worse clinical prognosis, which may be attributed to smoking-induced impairments in immune function and upper respiratory tract integrity.