The causative agent of both shingles and chickenpox is varicella-zoster virus. Varicella-zoster virus is categorized into primary infection and secondary infection according to the type of infection. 1. Primary infection: mainly manifested as chickenpox. Varicella-zoster virus infection begins in the respiratory mucosa, proliferates in local lymph nodes, then enters the blood and lymphatic system, replicates in the liver and spleen causing a second viremia, and finally spreads to the skin throughout the body. Chickenpox in children is generally self-limiting and has mild symptoms. Adult chickenpox is generally more serious and has a high mortality rate. 2. Secondary infection: mostly manifested as herpes zoster. After primary infection, varicella zoster virus is latent in the posterior root ganglia of the spinal cord or sensory ganglia of the brain nerves. When immunocompromised, the latent varicella-zoster virus is activated and travels along the axons of the sensory nerves to the skin cells they innervate, where it proliferates and causes herpes. Therefore, herpes zoster and chickenpox have the same virus, varicella-zoster virus, and patients are advised to seek prompt medical attention and treatment as prescribed by the doctor.