1. What is herpes zoster? Herpes zoster is an acute infection that often involves the dorsal root ganglion and the skin innervated by it. (Herpeszoster and shingles are both called herpes zoster, the former from the Greek meaning “crawling girdle” and the latter from the Latin meaning “belt, girdle”). 2. What is the cause of shingles? Herpes zoster is caused by varicella virus infection. After recovery from childhood varicella infection, the viruses are latent in satellite cells of the dorsal root ganglion and are reactivated when host immune function is reduced, such as by cold, old age, malignancy, HIV infection, and use of immunosuppressive drugs. Activated proto-dormant viruses can cause a very intense necro-inflammatory response in the dorsal root ganglia and dorsal horn of the spinal cord. In turn, the virus spreads retrogradely along sensory nerve fibers to the skin, causing severe skin pain and blistering, with a distribution of the dermal area consistent with the infected peripheral and central nerves. Jian Zhou, Pain Department, Foshan Chancheng District Central Hospital 3. What are the clinical manifestations of herpes zoster? The clinical manifestations are generally severe neuralgia, segmental blistering rash, rash mostly distributed along a peripheral nerve, arranged in a band, and the preferred site is the intercostal nerve. However, special types of herpes zoster should be noted: herpes zoster of the eye, herpes zoster of the ear, herpes zoster meningoencephalitis, herpes zoster of the viscera, etc. These special types of herpes zoster can be serious, and some can lead to blindness, deafness, or even death. Some cases can be misdiagnosed as angina pectoris, biliary or renal colic due to early pain only, so clinical caution should be exercised. 4.What is postherpetic neuralgia (PHN)? Postherpetic neuralgia is defined as pain that persists for more than one month after the clinical cure of acute herpes zoster. Postherpetic neuralgia is one of the most persistent pain disorders in the middle-aged and elderly population and is still a world-class pain problem. The duration of pain can be as short as 1 to 2 years or as long as 10 years, with a general history of 3 to 5 years. Patients suffer from chronic pain. Patients suffer from heavy psychological burden, depression, sleep disorders, poor quality of life, reduced ability to work and socialize, and even loss of confidence in life. The incidence of postherpetic neuralgia is proportional to the increase in age, according to relevant data: 49% for 50-59 years old, 65% for 60-69 years old, and 74% for 70-79 years old. The incidence of postherpetic neuralgia will continue to increase as the elderly population in China increases. 5.Postherpetic neuralgia (PHN) clinical manifestations? Usually, patients with PHN complain of three types of pain: persistent burning pain, paroxysmal irritation pain, pins and needles pain, and also complaints of tactile nociceptive abnormalities. 80-90% of patients present with nociceptive abnormalities that are dynamic in nature, such as pain induced by motor stimulation. For this reason, many patients experience severe pain when they wear clothing and rub their skin. Nurmikko et al. demonstrated that the affected segment has altered skin sensations of warmth, cold, thermal pain, touch, pins and needles, vibration and two-point position discrimination compared to the normal contralateral side. In addition to sensory loss and pain abnormalities, the skin is usually pigmented and crusted.