Definition and overview of shingles The cause of shingles. Chickenpox occurs when children who are immune to this virus are infected. Some patients become infected and become viral carriers without developing symptoms. Because of the neurophilic nature of the virus, it can be latent in the neurons of the posterior root ganglion of the spinal nerve for a long time after infection. The rash is generally unilateral and distributed by nerve segments, with clusters of herpes, and is accompanied by pain; the older the age, the more severe the neuralgia. The disease is known as herpes zoster in modern medicine and as snake bile sores in folklore. The prevalent age is mostly middle-aged and elderly. Long-term use of steroidal corticosteroids or immunosuppressants is common. The duration of the disease is usually about half a month. The skin areas innervated by the intercostal nerve and trigeminal nerve are the most common sites. The rash is characterized by the appearance of clusters of papules and blisters, corn to green bean size, with clear fluid, which may be bloody or necrotic ulcers in severe cases, on the basis of flushing. The rash is characterized by a unilateral distribution in the form of bands. Self-perceived symptoms are painful and intolerable. The pain may occur before the rash appears and is manifested by sensory hypersensitivity and pain induced by light touch. The pain often persists until the rash has completely resolved, sometimes for several months. The rash begins as a redness of the skin, followed by clusters of green bean-sized papules, which rapidly evolve into blisters 1-2 days later, with the blisters developing along the proximal end of the nerve in a band-like arrangement. After healing, temporary erythema or hyperpigmentation remains. The rash is often preceded by fever, malaise, loss of appetite, swollen local lymph nodes, and sensory allergy or neuralgia in the affected area, but there may be no prodromal symptoms. The lesions appear as localized flushing of the skin, followed by clusters of corn-sized papules, which rapidly turn into blisters with clarified blistering fluid and tense, shiny walls surrounded by a red halo. The lesions are distributed along one side of the dermal nerve and arranged in a band, with normal skin between the clusters of blisters. The lesions usually do not exceed the median line. Neuralgia is a characteristic feature of the disease and may precede or accompany the rash. In children, the pain is often mild or absent, while in older patients it is severe and often remains long after the damage has subsided. The onset of the disease is rapid and dramatic, lasting about 2 weeks. Temporary hyperpigmentation may remain after healing, and there is usually no scarring if there is no secondary infection.