Herpes Zoster: Description:
Also called as Shingles.
An infection caused by a herpes virus (varicella-zoster virus), characterized by an eruption of groups of vesicles on one side of the body following the course of a nerve due to inflammation of ganglia and dorsal nerve roots resulting from activation of the virus, which in many instances has remained latent for years following a primary chickenpox infection; the condition is self-limited but may be accompanied by or followed by severe postherpetic pain. See Also: varicella. Syn: shingles, zona [TA], zoster.
Herpes zoster, commonly known as shingles, is caused by the same virus responsible for chicken pox. After the initial exposure, herpes zoster lies dormant in certain nerve fibers. It may become active as a result of many factors such as: aging, stress, suppression of the immune system, and certain medications.
Shingles has no incubation period; it is caused by reactivation of latent infection from primary chickenpox disease. Shingles is infectious until all lesions have crusted over. Infectiousness can be prolonged in immunocompromised patients.
Because of the layout of the nerves that herpes zoster resides in, it only affects one side of the body or face during an outbreak. It begins as a rash that lead to blisters and sores on the skin. When the nerve branch that supplies the eye is involved, the forehead, nose, and eyelids may also be affected. Sores on the nose are a key signal of possible eye involvement.
Herpes zoster can cause several problems with the eye and surrounding skin that may have long term effects. Inflammation and scarring of the cornea, along with conjunctivitis (inflammation of the conjunctiva) and iritis (inflammation of the iris) are typical problems that require treatment. In some cases, the retina and optic nerve are involved. Eye problems caused by severe or chronic outbreaks of herpes zoster may include: glaucoma, cataract, double vision, and scarring of the cornea and eyelids.
Many who experience this infection find it extremely painful. This acutely painful phase usually lasts several weeks; however, some continue to experience pain or neuralgia long after the outbreak has cleared. This is known as post-herpetic neuralgia.
Shingles is found worldwide and has no seasonal variation. The most striking feature of the epidemiology of shingles is the increase in incidence found with increasing age. Decreasing cell mediated immunity (CMI) associated with aging is thought to be responsible for these increased rates. Similarly, the loss of CMI among persons with malignancies and HIV infection is thought to be responsible for higher rates of shingles among those populations. Approximately 20 percent of the general population will experience shingles during their lifetime and an estimated 500,000 episodes of shingles occur annually in the U.S. Approximately 4 percent of individuals will experience a second episode of shingles.
Herpes zoster can now be prevented, at least in some people. The FDA approved the first live VZV vaccine, called Zostavax (Oka/Merck), in May 2006. The single-dose vaccine contains 18,700 to 60,000 plaque-forming units of virus, considerably more than the approximately 1,350 plaque-forming units found in the Oka/Merck VZV vaccine for prevention of varicella in children. The VZV vaccine reduces herpes zoster incidence by half and postherpetic neuralgia by two-thirds in adults at least 60 years old, according to a study involving more than 38,000 people. Adverse effects are limited to mild injection-site reactions, itching and headache. Use of the vaccine is not yet widespread. The Advisory Committee on Immunization Practices unanimously endorsed the usage of VZV vaccine for all adults age 60 and older. A cost-effectiveness model suggested that VZV vaccination to prevent herpes zoster in immunocompetent older adults could increase quality-adjusted survival by 0.6 days compared with no vaccine. The vaccine would be cost effective only for adults age 60 to 69 if it cost less than $200 and if efficacy exceeded 30 years. Doctors do not yet know whether varicella vaccination in childhood, which became routine relatively recently, plays any role in preventing herpes zoster.
The first symptom is usually one-sided pain, tingling, or burning. The pain and burning may be severe.
Red patches on the skin form, followed by small blisters that look very similar to early chickenpox. The blisters break, forming small ulcers that begin to dry and form crusts. The crusts fall off in 2 to 3 weeks.
The rash usually involves a narrow area from the spine around to the front of the belly area or chest. It may involve face, eyes, mouth and ears.
Additional symptoms may include:
- Difficulty moving some of the muscles in the face.
- Drooping eyelid (ptosis).
- Fever General ill-feeling.
- Genital lesions.
- Hearing loss.
- Joint pain.
- Loss of eye motion (ophthalmoplegia).
- Swollen glands (lymph nodes).
- Taste problems.
- Vision problems.
These symptoms subside once the rash breaks out. One or more tiny raised red bumps appear first, most often on the face, chest, or abdomen. They become larger within a few hours and spread quickly, eventually forming small blisters on a red base. The numbers of blisters vary widely. Some patients have only a few spots, others can develop hundreds. Each blister is filled with clear fluid that becomes cloudy in several days. It takes about 4 days for each blister to dry out and form a scab. During its course, the rash itches, sometimes severely. Usually separate crops of blisters occur over 4 – 7 days, and the entire disease process lasts 7 – 10 days.
Causes and Risk factors:
Herpes zoster, or shingles, is caused by the same virus that causes chickenpox. After an episode of chickenpox, the virus becomes dormant in the body. Herpes zoster occurs as a result of the virus re-emerging after many years.
The cause of the re-activation is usually unknown, but seems to be linked to aging, stress, or an impaired immune system. Often only one attack occurs, without recurrence.If an adult or child is exposed to the herpes zoster virus and has not had chickenpox as a child or received the chickenpox vaccine, a severe case of chickenpox may develop, rather than shingles.
After infection with chickenpox, the virus resides in a non-active state in the nerve tracts that emerge from the spine. When it is re-activated, it spreads along the nerve tract, first causing pain or a burning sensation.The typical rash appears in 2 to 3 days, after the virus has reached the skin. It consists of red patches of skin with small blisters (vesicles) that look very similar to early chickenpox. The rash often increases over the next 3 to 5 days. Then, the blisters break, forming small ulcers that begin to dry and form crusts. The crusts fall off in 2 to 3 weeks, leaving behind pink healing skin.
Lesions typically appear along a single dermatome (the body area served by a single spinal nerve) and are only on one side of the body (unilateral). The trunk is most often affected, showing a rectangular belt of rash from the spine around one side of the chest to the breastbone (sternum).Lesions may also occur on the neck or face, particularly along the trigeminal nerve in the face. The trigeminal has three branches that go to the forehead, the mid-face, and the lower face. Which branch is involved determines where on the face the skin lesions will be.Trigeminal nerve involvement may include lesions in the mouth or eye. Eye lesions may lead to permanent blindness if not treated with emergency medical care.
Involvement of the facial nerve may cause Ramsay Hunt syndrome with facial paralysis, hearing loss, loss of taste in half of the tongue and skin lesions around the ear and ear canal. Shingles may, on occasion, involve the genitals or upper leg.
Shingles may be complicated by a condition known as post-herpetic neuralgia. This is persistence of pain in the area where the shingles occurred that may last from months to years following the initial episode. This pain can be severe enough to be incapacitating. The elderly are at higher risk for this complication.
Herpes zoster may affect any age group, but it is much more common in adults over 60 years old, in children who had chickenpox before the age of one year, and in individuals whose immune system is weakened. The disorder is common, with about 600,000 to one million cases in the U.S. per year.
Most commonly, an outbreak of shingles is localized and involves only one dermatome. Widespread or recurrent shingles may indicate an underlying problem with the immune system such as leukemia, Hodgkin’s disease and other cancers, atopic dermatitis, HIV infection, or AIDS. People with suppressed immune systems due to organ transplant or treatment for cancer are also at risk.
In general, once herpes zoster isfully developed, the clinical appearanceis distinctive from any otherdisease. Herpes zoster can be confused,however, with “zosteriform”herpes simplex virus infection, especiallyin the sacral area.Immunocompetent patients with ahistory of recurrent “shingles” (?2episodes) often have recurrent herpessimplex virus infection ratherthan herpes zoster.Diagnosis is more difficult inpatients with dermatomal painbefore developing skin lesions.Consider a broad differential diagnosisof localized pain in patientswho present before the rashappears.
The diagnosis may not be herpes zoster if the patient:
Has a rash without pain ordysesthesias.
- Has a rash that does not conformto the typical dermatomal distribution.
- Has persistent neuralgic painwithout the appearance of a typicalskin eruptionWhen the presentation is atypicalor complex, consultation may benecessary.
- Consult an infectious diseasespecialist or dermatologist forassistance with recognizingatypical presentations or withprocedures such as viral cultureor skin biopsy.
- Consult an ophthalmologist forassistance with diagnosing herpeszoster involving the first divisionof the trigeminal nerve.
- Consult an otolaryngologist forassistance with diagnosingRamsay Hunt syndrome.
When the clinical diagnosis of herpeszoster is not obvious, laboratoryconfirmation is important, especiallywhen antiviral therapy is planned.Possible tests include:
Viral culture: Recovery of VZV is highlydependent on the stage of the lesions,the quality of the specimen collectedand the time elapsed between specimencollection and inoculation of tissueculture. For maximum yield, fluid fromfresh vesicles should be aspirated into atuberculin syringe containing viral transportmedia and delivered immediately tothe virology laboratory. If there is deliverydelay, the specimen should be refrigeratedor stored on wet ice, not frozen.Growth of VZV in tissue culture maytake 3-14 days. The test is 30% to 70%sensitive and 100% specific.
Antigen detection: Direct fluorescentantigen assay is more sensitive thanviral culture. Using a modified Tzancktechnique, cells are scraped from thebase of the lesion with a scalpel bladeor the bevel edge of a large-gauge needle,smeared on a glass slide, thenstained using fluorescein-conjugatedmonoclonal antibodies to detect viralglycoproteins. Unlike a traditional Tzancksmear, direct fluorescent antigen assay(DFA) can distinguish between herpessimplex virus and VZV.
Serology: Patients with herpes zosterwill, by definition, be VZV seropositiveat the onset of illness.Although somepatients will show an enhanced VZVantibody titer after an episode of herpeszoster, serology is not a very sensitiveor specific diagnostic method. Mostlaboratories use enzyme-linked immunosorbentassay (ELISA) or latex agglutinationmethods; more sensitive assayssuch as the fluorescent antibody tomembrane antigen test and glycoproteinELISA are not widely available. The latexagglutination test is generally more sensitivethan ELISA for detecting VZV antibodyafter natural infection orvaccination. Commercial ELISA testsrange in sensitivity from 86%-97% andrange in specificity from 82%-99% indetecting antibody after natural varicellainfection but are less reliable for detectingantibody after vaccination.
PCR: Useful for detecting VZV DNA influids (e.g., cerebral spinal fluid). Notwidely available. Sensitivity and specificityare unknown. Polymerase chainreaction on cerebral spinal fluid is thetest of choice along with antibody testingfor VZV in patients with suspectedVZV myelitis, vasculopathy or zostersine herpete (herpes zoster with abnormalskin sensations and pain in a dermatomaldistribution but without a rash).
Herpes zoster usually disappears on its own, and may not require treatment except for symptom relief, such as pain medication.
Acyclovir is an antiviral medication that may be prescribed to shorten the course, reduce pain, reduce complications, or protect an immunocompromised individual. Desciclovir, famciclovir, valacyclovir, and penciclovir are similar to acyclovir and may be used to treat herpes zoster. For the greatest effect, treatment with acyclovir-like medications should start within 24 hours of the appearance of pain or burning sensation, and preferably before the appearance of the characteristic blisters.
Typically, the drugs are given as pills, in doses four times greater than those recommended for herpes simplex or genital herpes. Severely immunocompromised individuals may require intravenous (IV) acyclovir therapy.
Corticosteroids, such as prednisone, may occasionally be used to reduce inflammation and risk of post-herpetic neuralgia. They have been shown to be most effective in the elderly population. Corticosteroids have certain risks that should be considered before using them.
Pain medicines (analgesics, mild to strong, may be needed to control pain. Antihistamines may be used topically (direct application to the body) or orally (by mouth) to reduce itching. Zostrix, a cream containing capsaicin (an extract of pepper), may prevent post-herpetic neuralgia.
Cool wet compresses can be used to reduce pain. Soothing baths and lotions, such as colloidal oatmeal bath, starch baths, or lotions and calamine lotion, may help to relieve itching and discomfort. Resting in bed until the fever goes down is recommended.
The skin should be kept clean, and contaminated items should not be re-used. Non-disposable items should be washed in boiling water or otherwise disinfected before re-use. The person may need to be isolated while lesions are oozing to prevent infection of others — especially pregnant women.
Medicine and medications:
Acyclovir (Zovirax), famciclovir (Famvir), and valacyclovir (Valtrex) are approved for shingles. Acyclovir is the oldest, most studied of these drugs, but either famciclovir (Famvir) or valacyclovir (Valtrex), which are both metabolized into acyclovir, are now preferred to treat herpes zoster in most patients. They relieve symptoms better than acyclovir and require fewer daily doses (typically three) than the five doses needed with acyclovir.
The following drugs related to Herpes Zoster.
- Acyclovir Oral.
- Famvir Oral.
- Zovirax Oral.
- Famciclovir Oral.
- Acyclovir Sodium IV.
- Valacyclovir Oral.
- Corticotropin Inj.
- Acthar H.P. Inj.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.