Parotid Space, a Different Space from Other Deep Neck Infection Spaces

Deep neck infections (DNIs) such as parotid abscesses are medical emergencies with a seemingly different etiology and treatment course from other DNIs. We sought to confirm this in the present retrospective population-based cohort study. Between August 2016 and January 2020, 412 patients with DNIs seen at a tertiary medical center were enrolled in this study. Infections of the parotid space were compared with those of other deep neck spaces, according to patient characteristics. All patients were divided into parotid space (PS; n = 91, 22.08%) and non-parotid space (NPS; n = 321, 77.92%) subgroups. We further divided the patients into single parotid space (PS-single; n = 50, 12.13%), single non-parotid space (NPS-single; n = 149, 36.16%), multiple parotid space (PS-multiple; n = 41, 9.95%), and multiple non-parotid space (NPS-multiple; n = 172, 41.76%) DNI subgroups. In the PS-single and PS-multiple subgroups, a longer duration of symptoms (p = 0.001), lower white blood cell count (p = 0.001), lower C-reactive protein level (p = 0.010), higher rate of ultrasonography-guided drainage (p < 0.001), and lower rates of surgical incision and drainage (p < 0.001) were observed compared with the NPS-single and NPS-multiple subgroups. The PS group had a higher positive Klebsiella pneumoniae culture rate (p < 0.001), and lower positive Streptococcus constellatus (p = 0.002), and Streptococcus anginosus (p = 0.025) culture rates than the NPS group. In a multivariate analysis, K. pneumoniae was independently associated with parotoid space involvement in comparisons of the PS and NPS groups, PS-single and NPS-single subgroups, and PS-multiple and NPS-multiple subgroups. The clinical presentation of a parotid space infection differs from that of other deep neck space infections.