It infects the body once, but the risk for relapse continues throughout a person’s life. This is about the virus that causes herpes zoster. The first time it affects the organism, varicella zoster virus manifests as chickenpox. However, after it has been neutralized by the immune system, it rests in the nervous system, where it can remain in a dormant state for many years. Eventually, however, it awakens and following nerve pathways it affects the skin, taking the clinical form of herpes zoster.
Symptoms and transmissibility
During the first days, the patient feels pain, a burning sensation and tingling in the area that is infected by the virus. After a few days a vesicular eruption appears on the skin, which may last 7-10 days and it progresses as follows: initially red spots appear, on which blisters with liquid are progressively formed, which then break and finally a crust develops. The rash causes itching, while the patient may even have d fever, chills, malaise, headache and fatigue.
Diagnosis is facilitated by the distribution of the rash, which essentially follows the path of the nerve where the virus was “hidden”. Its characteristic is that it covers – creating a zone – on one side of the body, showing particular preference on the chest, the lumbar region and the face.
A patient who has developed herpes zoster can transmit the varicella zoster virus to anyone without immunity to chickenpox. Usually transmission occurs when someone comes in contact with the open sores of the patient. This person, though, will develop chickenpox, not herpes zoster. Patients should avoid contact with other people, especially newborn babies, pregnant women and people with weak immune system, at least for the period that the blisters have not developed a crust.
Another important thing to note is that weak immune system is a risk factor for the virus’ “awakening”, too. This is why people with HIV/AIDS or cancer are in particular risk, as well as people under chemotherapy, patients receiving special immunosuppressive drugs to prevent organ rejection or those who are taking steroids for long periods of time, as well as people over the age of 50.
Postherpetic neuralgia (PHN) is the most common complication of herpes zoster (shingles). It produces chronic pain along cutaneous nerves and often some distortion of sensation, and it is due to the damaged nerve fibres that send excessive pain messages to the brain. It may also cause neurological disorders, which depending on the affected nerves, may lead to encephalitis, facial paralysis, problems with hearing and balance. If herpes zoster appears on the periocular areas, i.e. the area around the eyes, it may lead to painful ocular infections or even loss of sight, and if the blisters are not treated appropriately, there is a possibility of local skin bacterial infections development.
First line treatment and management of possible complications
Despite the fact that herpes zoster cannot be cured, timely management, within the first 72 hours from the development of the blisters, is important so that to accelerate the healing of the lesions, as well as for the limitation of pain and prevention of complications. The antiviral drugs aciclovir, valaciclovir and famciclovir are the first treatments. In general, treatment duration is approximately seven days. Among the possible side effects, nausea, headache and gastrointestinal disorders are included. Apart from this, medication is safe and well tolerated to a large extent. Dosage should be appropriately defined for patients with renal failure, as these medicines are excreted through the kidneys.
For the management of pain that occurs during the acute phase of herpes zoster, as well as in postherpetic neuralgia it is possible to administer antiepileptic medication (gabapentin and pregabalin), opioid analgesics (hydrocodone and oxycodone), tricyclic antidepressants (nortriptyline, amitriptyline, and desipramine), and anaesthetic adhesive plasters of lidocaine and capsaicin cream.
As far as prevention is concerned, vaccination is the best choice. Primarily, the vaccine for chicken pox is included in the standard vaccination schedule of infants and is recommended for adults that have not been vaccinated in childhood. Although the vaccine does not guarantee that one will not become infected, it limits the risk of complications, and the severity of the disease
Furthermore, since 2011, the US Food and Drug Administration (FDA) has given the green light for the administration of a vaccine against herpes zoster to people above the age of 50, who are among the high-risk group of people. Recently scientists from the United Kingdom that studied the medical records of 750,000 patients aged over 65 noticed that those who had received the vaccination had 50% less risk of disease manifestation and 60% less likely to develop complications of viral infection, especially postherpetic neuralgia.