What is herpes zoster?
Herpes zoster is an acute infection caused by the varicella-zoster virus (VZV), which mostly affects adults. It is characterized by the development of cutaneous rashes in the form of blisters or painful vesicles, which are located following the path of some inflamed nerve also by the virus. Because of this particular disposition the infection is popularly known as ‘ shingles ‘. In some Mediterranean countries it is also called the San Antonio Fire.
This type of herpes is produced by the same virus as chickenpox, being a reactivation of it at the level of the nerve nodes where it remains in a dormant state to break into certain health conditions in the form of herpes zoster. This relationship is known since 1892 where cases of chickenpox were observed after various contacts with people with shingles.
Although 95% of individuals at 18 years of age already have antibodies to the virus from vaccination or infection caused by this virus, not everyone will develop neurocutaneous involvement. There must be a number of circumstances for this to happen (alterations of the immune system, well permanent transient for some disease).
Initiating an appropriate antiviral treatment early decreases discomfort and avoids painful complications.
Incidence of herpes zoster and prognosis
Herpes zoster will affect about 20% of the population. It can be presented at any age, although the most common is that it appears in over 60 years or people with an immune system depleted by some illness or medical treatment.
In children it is usually a benign process, but in the case of adults it can become a very debilitating disease, because it can cause great pain. In 4% of cases, a second outbreak of herpes zoster is reappearing and up to 30% in the case of HIV-infected patients.
It will be important to determine some hidden cause when a young adult develops this disease, for example, a study that looks for malignant diseases or debilitating infections such as HIV infection.
Involvement in children under 2 years of age is believed to be the result of a mother’s chickenpox process during pregnancy, i.e., an intrauterine infection by the virus. It is also noteworthy that the appearance of herpes zoster in pregnant women poses no special risk in the fetus, although it is advisable not to treat it with antivirals intended for this purpose except in very severe cases.
Usually it is a problem that usually persists about a month until it disappears on its own, although measures can be put in place to treat the symptoms. However, in some immunosuppressed or elderly patients, some complications may appear, such as postherpetic neuralgia, which may become disabling. If herpes affects the face, it can cause facial paralysis, eye problems, auditory or encephalitis.
Main causes of herpes zoster
The herpes zoster patient is often infected in childhood. In this first moment develops a disease pox (with reddish rashes in the skin) known as chickenpox, which constitutes the initial form of infection of the varicella-zoster virus. After the chickenpox has been resolved, the virus remains dormant for years in the ganglions of the patient’s dorsal nerves. The reactivation of this virus, which was inactivated, is the cause of herpes zoster.
The two main factors by which the latent virus of chickenpox sprouts and manifests in the form of zoster are:
» The functional alteration of immunity, being the clear example of aging, where the functioning of this system and others deteriorate. There are cases in young adults and without other illnesses, but with debilitating situations (nutritional, stress …) where it can appear, although the study is obliged to exclude other processes.
» Pathological alteration of the immune system due to medication (corticoids, chemotherapy), tumors, or infections such as HIV.
The transmission of the virus is likely to occur by respiratory. Chickenpox is known to be an extremely contagious disease; The patient may contaminate other people from a day before up to five days after the appearance of the vesicles. Even some babies whose mothers suffered from chickenpox during pregnancy have developed herpes zoster during the first two years of life.
Also, children who had chickenpox before the first year of life have more ballots to suffer from this problem.
It has also been observed that some medications, such as some of the employees in the treatment of rheumatic pathologies such as osteoarthritis, may favour their appearance.
Main symptoms of herpes zoster
Among the symptoms of herpes zoster We can find the following:
• Painful vesicles occur along the path of some nerve (more frequently thoracic or lumbar). It usually affects only one side of the body. These vesicles can grow for three to five days and end up joining each other, thus forming large blisters. This is the main symptom of herpes zoster. After the blisters a crusted phase occurs, which is the final phase of the cutaneous lesion where the risk of infection of the lesions is much lower.
• Gastrointestinal disorders, general malaise, fever, and headache may arise before the onset of vesicles. Pain in the affected nerve is then present, which precedes in 2-3 days to the appearance of the vesicles.
• Pain is one of the characteristics of this ailment, and may even appear up to 2-3 days before the blisters sprout. It is due to the inflammatory affectation that the virus produces precisely in the nodes where it remained in latent state.
• One of the most important complications of herpes zoster is postherpetic neuralgia, which can occur up to 50% of people over 50 years, and causes permanent or intermittent pain in the affected nerve, even for more than a year past the cutaneous episode. The pain can get worse at night or with changes in temperature.
In some cases it becomes disabling, and it can also be accompanied by a deficit of sensitivity of the affected nerve. This is one of the most common sequelae of herpes zoster infection. It is more common when it is not treated with antivirals zoster, in women and when the affectation is ophthalmic. Against what can be thought, is not more frequent among the immunosuppressed.
• If the virus is lodged in cranial nerves, it can affect the eyelids and endanger the vision. It produces a keratitis that can be continued with glaucoma or severe iridocilitis.
• On rare occasions, the mandibular nerve is affected. This causes injuries to the palate, tonsils, floor of the mouth and even, in the tongue, and thus loses the sense of taste.
• Like herpes simplex, it can reach the central nervous system and cause meningitis (which will cause fever, headache and neck stiffness). It may cause motor paralysis as a result of spinal cord infection.
Other neuromuscular conditions associated with herpes zoster are:
» Guillain-Barre syndrome: The extremities present pain, weakness and paralysis. This painting is progressing, ascending to the trunk and face. Its evolution is variable; Some patients have minimal symptoms and others, however, may require hospital admission for weakness of the respiratory musculature. It is finally resolved spontaneously in a few weeks.
» Transverse myelitis: An inflammation of the spinal cord. It manifests with sensory and motor disturbances, which later evolve into paralysis of one or both legs. In most cases the progression of the symptoms stabilizes in about 10 days. There is no whole effective treatment, and its recovery is never complete.
» Myositis: Inflammation of a muscle, which carries pain and, if allowed to evolve, can cause necrosis.
Herpes zoster and AIDS
In recent years it has been observed that herpes zoster is a very common infection in people with AIDS. In these patients, the disease occurs more aggressively than normal. The formation of injuries can last for two weeks.
The total duration of the disease is usually two to ten days, however, it can take two to four weeks until the skin comes to recover its normal appearance.
Herpes zoster Treatment
It is not possible to remove the herpes zoster virus from the body by any treatment, even if certain medications may be taken to relieve or decrease symptoms and recover as soon as possible.
Acyclovir treatment is accepted for chickenpox and herpes zoster. This medicine, administered by mouth for 7-10 days, is very beneficial for patients with a reactivation of varicella-zoster virus. Its complicated dosage relegates only intravenous treatments in complicated cases.
Other drugs that are also very useful as treatment of herpes zoster are famciclovir and Valacilovir, which offer many advantages in terms of administration, as they require less daily doses. For a few years Brivudina was used by one dose a day for a week with a resolution rate of very high skin lesions, and a significant decrease in the incidence of postherpetic neuralgia.
Topical treatment of skin lesions should also be done to accelerate the crusting process and avoid discomfort and overinfection. For this purpose, the promotion of diluted zinc sulfate is usually applied. It is important to avoid tight clothing that rubs with injuries as it can cause discomfort and slow the process.
If there is ocular involvement, the patient should be referred to the ophthalmology service, where they will be given topical and systemic acyclovir for the treatment of herpes zoster.
In special cases, such as in AIDS patients or other states of immunosuppression, acyclovir should be used intravenously, so they will always require hospitalization. This reduces the possibility of later complications.
If there is postherpetic neuralgia, the most important thing will be the use of pain relievers. Amitriptyline hydrochloride and Fluphenazine hydrochloride have been used for this.
Others, indicated for epilepsy, such as gabapentin and pregabalin, are effective in controlling pain. Opioid analogues such as tapentadol are also used, with a good tolerance and a lower rate of adverse effects than conventional opioids, as well as patches of lidocaine on the sore area, but no blisters or scabs.
It has also been shown that early use of glucocorticoids has dramatically accelerated some aspects of improving the patient’s quality of life, such as the return to normal activity and the cessation of analgesic treatment.
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