Association between proinflammatory cytokines and pain intensity in patients with postherpetic neuralgia

Inflammatory response is involved in the pathogenesis of herpes zoster (HZ) and postherpetic neuralgia (PHN). This study aimed to evaluate levels of proinflammatory factors at different stages of HZ and PHN. A total of 154 patients within 72 h of HZ onset and 30 healthy controls were included. Patients were followed up to 90 days. The levels of interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α) and C-reactive protein (CRP) were measured at baseline and 90 days. The visual analogue scale (VAS) was used to assess the intensity of pain and PHN patients were divided into mild-to-moderate pain and severe pain group. Interleukin 6, TNF-α and CRP levels in HZ patients at baseline were significantly higher than in healthy controls and decreased as followed up to 90 days. Moreover, PHN patients had a higher level of IL-6, TNF-α or CRP at baseline and 90 days than non-PHN patients. In addition, PHN patients in the severe pain group had a notably higher baseline or 90-day IL-6, TNF-α and CRP level than in the mild-to-moderate pain group. However, the changes of IL-6, TNF-α and CRP levels between 90 days and baseline were significantly less pronounced in the severe pain group than in the mild-to-moderate pain group. The levels of proinflammatory cytokines were higher in HZ and PHN patients and associated with pain intensity in PNH patients. These findings suggest that repeated measurements of serum proinflammatory cytokines may aid in clinical management and guide anti-inflammatory treatment strategies.