Shingles or medically herpes zoster is a viral disease that manifests itself in blister-like, painful rashes in a strictly limited area of the body. It is caused by the varicella zoster virus (VZV). The varicella zoster virus belongs to the group of herpes viruses, i.e.
those viruses that also cause herpes labialis, i.e. lip herpes. A closer look at shingles reveals similarities to lip herpes, at least externally. Shingles got its name because of its belt-shaped appearance, around the body.
Sometimes the rashes also manifest themselves in the form of a half-sided “band”, so they do not necessarily surround the body completely. A good third of a million people in Germany suffer from shingles every year. Two thirds of those affected are over 50 years old.
This shows the correlation between age and occurrence of the disease. While in younger years the immune system can still successfully suppress an outbreak of the varicella virus, in old age it is often too weak to successfully counteract it. In addition, up to the age of 40 a good 98% of the population is infected with the Varicella Zoster Virus (VZV), so that a later outbreak is very likely. In patients over 85 years of age, the risk for an outbreak of shingles is even higher than 50%.
Cause of shingles
An outbreak of shingles is the result of a reactivation of the varicella viruses already present in the body. Especially stress, immunodeficiency and age are responsible for a new outbreak. Shingles is strictly limited to one area, for example the neck.
This is due to the fact that the viruses settle in the spinal ganglia in the spinal cord. A spinal ganglion is a nerve fiber complex that is located in pairs to the right and left of a vertebral body and originates from the spinal cord. It is in this spinal ganglion that the varicella viruses can now settle and hibernate, so to speak.
Normally they are kept in check by our immune system, but when it is otherwise busy, the varicella viruses sense their chance and spread along the nerve fibers of the spinal ganglion. Since a spinal ganglion is always responsible for a precisely defined area, shingles does not occur throughout the entire body, but only in a specific segment, for example the neck. In this way, it is also possible to trace back directly from which vertebral body segment the viruses originated: Namely segment C3 (vertebral body number 3).
The segment that is served by the spinal ganglion or vertebral body is also called the dermatome. A dermatome is the projection of a vertebral body and its nerve fibers onto a specific skin area. In the case of shingles, the actual dermatome of the spinal ganglion is affected, as are usually the one or two adjacent dermatomes. Only very severe immune deficiency can lead to a complete physical infestation.
