When viruses awaken

After healing, however, the virus does not disappear from the body, but nests in the ganglia of the spinal nerves and the cranial nerves. Reactivation can be asymptomatic or lead to a second manifestation, herpes zoster, or "zoster" for short. The neurocutaneous viral disease can basically occur at any age. However, the risk increases with age, so that mainly people over 50 are affected. An immune deficiency, whether caused by the disease or as a consequence of therapy, can also lead to the dormant viruses replicating again.

In about 80 percent of patients, zoster is announced with prodromal symptoms. These include non-specific complaints such as mild fever, tiredness and fatigue. When the viruses spread along nerve pathways and cause inflammation, symptoms appear in the affected skin area (dermatome). Typical symptoms are pain or sensory disturbances and, as the main manifestation, a skin rash consisting of blisters arranged in groups and filled with a serous fluid. The blisters burst open after a few days, dry up and crust over. The efflorescences usually only appear on one half of the body and are predominantly on the trunk, with increasing age also on the head. Infestation of the arms or legs is rare.

However, the burning nerve pain is usually more stressful for those affected. It occurs in the area supplied by the affected nerve. If the pain lasts longer than three months, it is called postzosteric neuralgia (PZN). Those affected sometimes continue to suffer from sudden attacks of pain, intense pain on touching and strong sensitivity to touch for years. The pain is due to partial nerve lesions and affects the quality of life. Further complications can acutely or chronically affect the skin, eye (zoster ophthalmicus), ear (zoster oticus) or internal organs. Around 20 percent of patients over 60 years of age have persistent symptoms that last longer than a year.

In young immunocompetent people without risk factors and with a very mild course, viral treatment can be dispensed with. The situation is different for patients over 50 years of age with immune deficiencies, certain underlying diseases or a severe or complicated course of zoster. According to the 2019 guideline "Diagnosis and therapy of zoster and postzoster neuralgia", they need systemic antiviral chemotherapy, local antiseptic therapy and consistent pain therapy as early as possible.

The later antiviral therapy starts, the less effective can it be. In addition, rapid and efficient antiviral treatment reduces the risk of complications such as PZN developing. Ideally, treatment with systemic antivirals should begin 72 hours after the vesicles have appeared. Topical antiviral therapy is not sufficient. In an uncomplicated course, patients take aciclovir, famciclovir, valaciclovir or brivudine orally. The nucleoside analogues are almost equally effective in reducing fever, stopping vesicular eruption, accelerating healing of skin lesions and relieving acute zoster pain, and each must be taken for seven days. There are differences in dosage. Patients use aciclovir five times a day, valaciclovir and famciclovir three times a day and biruvidine only once. Brivudine, valaciclovir and famciclovir are superior to orally administered aciclovir because of their better pharmacokinetics, bioavailability and easier administration. Venous administration of aciclovir is indicated in patients with a severe course, zoster in the head region or under immunosuppression.