Herpes zoster (HZ), resulting from the reactivation of the varicella‐zoster virus, is a significant disease. This study aimed to explore the factors influencing sensory neuron involvement in HZ at different locations and its association with postherpetic neuralgia (PHN). A total of 3143 cases were retrieved from an electronic medical record system, including 2676 cases of HZ and 467 cases of PHN. Gender, age, site of onset, past surgical history, and comorbidities were analyzed using a multifactorial logistic regression model. The results revealed correlations between age, gender, comorbidities (diabetes, coronary heart disease, percutaneous coronary intervention [PCI]), and sensory neuron involvement in HZ. Specifically, older age, female gender, and comorbid conditions such as diabetes/coronary heart disease were associated with sacral dorsal root ganglion (DRG) involvement, while PCI history was associated with lumbar DRG involvement. Additionally, sensory neuron involvement at different locations by HZ was linked to PHN. Furthermore, independent risk factors for PHN included thoracic DRG involvement, older age, and comorbidities (diabetes, surgical history, malignancy). It is crucial to prevent damage to the DRG, especially in individuals with comorbidities, through activities avoidance and active treatment, to minimize the occurrence of PHN.