Shingles and Chickenpox (Varicella-Zoster Virus)

Description

Alternative Names

Complications

Chickenpox rarely causes complications, but it is not always harmless. Five out of every 1000 children who have the infection require hospitalization, and, in rare cases, chickenpox can be fatal. In the past, chickenpox has caused about 11,000 hospitalizations each year and 100 deaths in the US. Widespread vaccination, however, has produced a dramatic decline in these numbers.

Adults have the greatest risk for dying from chickenpox, with infants having the next highest risk. And, in general, the percentage of adults dying from chickenpox compared to children is increasing in Western nations. In fact, one study reported that in the UK chickenpox is responsible for more deaths in adults than measles, mumps, whooping cough and Haemophilus influenzae type B meningitis combined. (It should be noted, however, the number of deaths is still very low. For example, in the UK where there is no widespread vaccination program, about 25 people die every year from chickenpox.)

Males (both boys and men) have a higher risk for a severe case of chickenpox than females. Children who catch chickenpox from family members are likely to have a more severe case than if they caught it outside the home. The older the child the higher the risk for a more severe case. But even in such circumstances, chickenpox is rarely serious in children. Other factors put individuals at specifically higher risk for complications of chickenpox.

Recurrence of Chickenpox and Reactivation as Shingles

Recurrence of Chickenpox. Recurrence of chickenpox is possible, but is very uncommon. One episode of chickenpox usually means life-long immunity against a second attack. (It should be noted that people who have had mild infections may be at greater risk for a breakthrough infection later on.)

Reactivation of the Virus as Shingles (Herpes Zoster). The major long-term complication of varicella is the later reactivation of the herpes zoster virus and the development of shingles, which occurs in about 20% of people who have had chickenpox.

Specific Complications of Chickenpox (Varicella)

Aside from itching, the complications described below are very rare, and parents should not be alarmed at all when their children develop this very common and ordinarily mild disorder.

Itching. Itching, the most common complication of the varicella infection, can be very distressing, particularly for small children. Certain home remedies are available that can alleviate the discomfort.

Secondary Infection and Scarring. Small scars may remain after the scabs have fallen off, but they usually clear up within a few months. In some cases, a secondary infection may develop at spot sites where the patient has scratched. The infection is usually caused by the bacteria Staphylococcus aureus or Streptococcus pyogenes. Permanent scarring may occur as a result. Children with chickenpox are at much higher risk for this complication than adults are, possibly because they are more likely to scratch.

Ear Infections. Some children are at higher risk for ear infections from chickenpox. Hearing loss is a very rare result of this complication.

Bacterial Superinfection. Bacterial superinfection of the skin caused by group A streptococcus is the most common serious complication of chickenpox. The infection is usually mild, but if it spreads in deep muscle, fat, or in the blood, it can be life threatening. Infection can cause serious conditions such as necrotizing fasciitis (the so-called flesh-eating bacteria) and toxic shock syndrome (TSS). One analysis indicated that streptococcus A is increasing and is a greater problem than previously thought, but it is still very rare.

Symptoms include the following:

• A persistent or recurrent high fever.
• Redness, pain, and swelling in the skin and the tissue beneath.

Pneumonia. Pneumonia should be suspected if coughing and abnormally rapid breathing develop in patients who have chickenpox. Adults and adolescents with chickenpox are at some risk for serious pneumonia. Pregnant women, smokers, and those with serious medical conditions, have an even higher risk for pneumonia if they have chickenpox. Oxygen and intravenous acyclovir are key components for treating this condition. One study suggested that corticosteroids might also prove useful for treating varicella pneumonia as well. Pneumonia that is caused by varicella can result in lung scarring, which may impair oxygen exchange over the following weeks, or even months.

Effects on the Brain and Central Nervous System.

• Inflammation in the Brain. Encephalitis and meningitis, infections or inflammation in the central nervous systems, have occurred in a few varicella patients, both children and adults. This condition can be very dangerous, causing coma and even death. Fortunately, it is extremely rare. Symptoms vary; the patient may become over-agitated or may exhibit loss of coordination and poor balance.
• Stroke. Although stroke in children is extremely rare, a condition called cerebral vasculitis, in which blood vessels in the brain become inflamed, has been associated with varicella-zoster. Varicella may be a factor in some cases of stroke in young adults. Again, the incidence of this is extremely rare.

Effects During Pregnancy. The risk for chickenpox in a pregnant woman is very low (one to seven cases in 10,000). However, chickenpox places the woman at risk for life-threatening pneumonia. Infection in the pregnant woman in the first trimester also poses a 1% to 2% chance for infecting the developing fetus, which is an extremely serious condition. (Herpes zoster is even rarer in pregnant women and there is almost no risk for the unborn child in such cases.)

Disseminated Varicella. Disseminated varicella, chickenpox that spreads to organs in the body, is extremely serious and is a major problem for patients with compromised immune systems. An immune system may become compromised as a result of diseases such as AIDS, inherited conditions, or certain drugs. For example, disseminated varicella occurs in up to 35% of children with chickenpox who are taking cancer chemotherapy; in such cases mortality rates are between 7% and 30%.

Reye's Syndrome. Reye's syndrome, a disorder that causes sudden and dangerous liver and brain damage, is a very rare complication of chickenpox and other viruses in children who take aspirin. The disease can lead to coma and is life threatening. Symptoms include rash, vomiting, and confusion beginning about a week after the onset of the disease. Because of the strong warnings against children taking aspirin, this condition is, fortunately, nearly nonexistent.

Other Rare Complications of Chickenpox. Other extremely rare complications of varicella include problems in blood clotting, and inflammation of the nerves in the hands and feet, and in other areas of the body, such as the heart, testicles, liver, joints, or kidney. Such cases of inflammation are almost always temporary in otherwise healthy patients.

Complications of Shingles (Herpes Zoster)

Pain. The pain and discomfort of the active herpes zoster infection is the primary symptom and complication of herpes zoster. The pain usually takes one or more of three forms:

• Continuous burning or aching pain.
• Periodic piercing pain.
• Spasm similar to electric shock.

Such experiences may also be more intense than even normal responses, defined in the following ways:

• Allodynia. This is pain caused by factors, such as a light touch of clothing or a cold wind, which occurs from very little stimulation.
• Hyperalgesia. This is a more intense painful response to a normally painful experience.

The pain tends to be more severe at night. Temperature changes can also affect pain. The pain may extend beyond the areas of the initial zoster attack, and some areas have no feeling at all. In most cases it does not affect daily life. On an encouraging note, in one study once a patient was free of zoster pain, it almost never recurred. Rarely, however, the pain of herpes zoster affects sleep, mood, work, and overall quality of life. This can lead to fatigue, loss of appetite, depression, social withdrawal, and impaired daily functioning.

Itching. Many patients report itching as the primary symptom, rather than pain. In rare cases, it can be disabling (called postherpetic itch). Little research has been conducted on this complication, but in one study, it tended to occur in women and when shingles affected the head, face, and neck.

Postherpetic Neuralgia (PHN). Postherpetic neuralgia (PHN) is pain that persists for longer than a month after the onset of herpes. It is the most common severe complication of shingles. It is not clear why PHN occurs. Some theories for its development are as follows:

• The herpes zoster virus appears to produce persistent inflammation in the spinal cord that causes long-term damage, including nerve scarring.
• Nerves that are injured in the initial attack may regrow abnormally and provoke an exaggerated response in the brain that signals intense sensitivity or pain.

Studies have reported a risk of PHN in people with herpes ranging from 10% to 70%. In general, however, the risk is likely to be in the lower range. The following are risk factors for PHN:

• Age. PHN affects about 25% of herpes zoster patients over 60 years old. In addition, the older a person is the longer PHN is likely to last. It rarely occurs in people under age 50.
• Gender. Some studies have suggested that women may be at slightly higher risk for PHN than men, although a 2000 study found no difference.
• Having Severe or Complicated Shingles. People who had prodromal symptoms or a severe attack (numerous blisters and severe pain) during the initial shingles episode are also at high risk for PHN. The rate is also higher in people whose eyes have been affected by zoster.
• Immune Factors. People with impaired immune systems do not seem to be at any higher risk for persistent PHN than those with normal immune systems.

In most cases, PHN resolves within three months. In fact, some experts define persistent pain after a herpes zoster attack as subacute herpetic neuralgia if it lasts between one and three months and as PHN only if it lasts beyond three months. According to studies in 2003 report, only about 10% of patients experience pain after a year. Furthermore, one study suggested that severe and very persistent PHN is not common. Unfortunately, when PHN is severe and treatments have not been very effective, the persistent pain and abnormal sensations can be profoundly frustrating and depressing for these patients.

Secondary Infection in the Blisters. If the blistered area is not kept clean and free from irritation, it may become infected with Streptococcus A or Staphylococcus bacteria. If the infection is severe, scarring can occur.

Guillain-Barre Syndrome. Guillain-Barre syndrome is caused by inflammation of the nerves and has been associated with a number of viruses, including herpes zoster. The arms and legs become weak, painful, and, sometimes, even paralyzed. The trunk and face may be affected. Symptoms vary from mild to severe enough to require hospitalization. The disorder resolves in a few weeks to months. It should be noted that other viruses (e.g., C. jejuni, cytomegalovirus, and Epstein-Barr) are reported to have a stronger association to this syndrome than herpes zoster does. One study, in fact, found no higher incidence of herpes zoster virus in Guillain-Barre patients than in the general population.

Effects on Face and Ears.

• Ramsay Hunt syndrome. Ramsay Hunt syndrome occurs when herpes zoster causes facial paralysis and rash on the ear (herpes zoster oticus) or mouth. Symptoms include severe ear pain and hearing loss, ringing in the ear, loss of taste, nausea, vomiting, and dizziness. Ramsay Hunt Syndrome may also cause a mild inflammation in the brain. The dizziness may last for a few days or even for weeks, but usually resolves. Severity of hearing loss varies from partial to total, however, this too usually always goes away. Facial paralysis, on the other hand, may be permanent.
• Bell's Palsy. Bell's palsy is partial paralysis of the face. There is some indication that this syndrome may suggest a reactivation of herpes zoster, even if no rash appears.

In some cases, it is difficult to distinguish between Bell's palsy and Ramsay Hunt syndrome, particularly in the early stages. Ramsay Hunt syndrome tends to be more severe than Bell's palsy. Although evidence is weak on treating facial involvement of herpes zoster, some experts recommend oral prednisone (a corticosteroid) and an antiviral agent within seven days of symptom onset. Even though nearly all cases of Bell's palsy and the majority of Ramsay Hunt syndrome resolve without problems, the possibility of residual symptoms with Ramsay Hunt and the early resemblance between the two syndromes warrants this treatment.

Effects on the Brain. Inflammation of the membrane around the brain (meningitis) or in the brain itself (encephalitis) is a rare complication in people with herpes zoster. The encephalitis is generally mild and resolves in a short period. In rare cases, particularly in patients with impaired immune systems, it can be severe and even life-threatening.

Effects in the Urinary Tract. In rare situations, herpes zoster can infect the urinary tract and cause difficult in urination. The condition is temporary but may require a catheter to eliminate urine in some patients who have prolonged difficulty in urinating.

Infections in the Eye. If shingles occurs in the face, the eyes are at risk, particularly if the path of the infection follows the side of the nose. If the eyes become involved (called herpes zoster ophthalmicus), a severe infection can occur that is difficult to treat and can threaten vision. AIDS patients may be at particular risk for a chronic infection in the cornea of the eye.

Herpes zoster can also cause a devastating infection in the retina called imminent acute retinal necrosis syndrome. In such cases, visual changes develop within weeks or months after herpes zoster outbreak has resolved. It should be noted that this complication does not always follow a herpes outbreak in the face but can occur after an outbreak in any part of the body. Prompt treatment with acyclovir can often halt its progress, at least in people with healthy immune systems. Acyclovir or valacyclovir, a similar agent, may prevent other eye complications, such as conjunctivitis (pink-eye), inflammation of the cornea, and pain.

Disseminated Herpes Zoster. As with disseminated chickenpox, disseminated herpes zoster, which spreads to other organs, can be serious to life-threatening, particularly if it affects the lungs. People with compromised immune systems are at greatest danger, with risk of 5% to 25%. It is very rare in people with healthy immune systems.

In very rare cases, herpes zoster has been associated with Stevens-Johnson syndrome, an extensive and serious condition in which widespread blisters cover mucous membranes and large areas of the body.