CHICKEN POX

Chickenpox is a highly contagious disease caused by primary infection with varicella zoster virus (VZV). It usually starts with avesicular skin rash mainly on the body and head rather than on the limbs. Chickenpox is an airborne disease which spreads easily through coughing or sneezing by ill individuals or through direct contact with secretions from the rash. A person with chickenpox is infectious one to two days before the rash appears. They remain contagious until all lesions have crusted over (this takes approximately six days). Immunocompromised patients are contagious during the entire period as new lesions keep appearing. Crusted lesions are not contagiousThe early (prodromal) symptoms in adolescents and adults are nausea, loss of appetite, aching muscles, and headache. This is followed by the characteristic rash or oral sores, malaise, and a low-grade fever that signal the presence of the disease. Oral manifestations of the disease (enanthem) not uncommonly may precede the external rash (exanthem). In children the illness is not usually preceded by prodromal symptoms, and the first sign is the rash or the spots in the oral cavity. The rash begins as small red dots on the face, scalp, torso, upper arms and legs; progressing over 10–12 hours to small bumps, blisters and pustules; followed by umbilication and the formation of scabs. These symptoms of chickenpox appear 10 to 21 days after exposure to a contagious person. Adults may have a more widespread rash and longer fever, and they are more likely to experience complications, such as varicella pneumonia.

Exposure to VZV in a healthy child initiates the production of host immunoglobulin G (IgG), immunoglobulin M (IgM), and immunoglobulin A(IgA) antibodies; IgG antibodies persist for life and confer immunity. Cell-mediated immune responses are also important in limiting the scope and the duration of primary varicella infection. After primary infection, VZV is hypothesized to spread from mucosal and epidermallesions to local sensory nerves. VZV then remains latent in the dorsal ganglion cells of the sensory nerves. Reactivation of VZV results in the clinically distinct syndrome of herpes zoster (i.e., shingles), postherpetic neuralgia, and sometimes Ramsay Hunt syndrome type II. Varicella zoster can affect the arteries in the neck and head, producing stroke, either during childhood, or after a latency period of many years.

Treatment mainly consists of easing the symptoms as there is no actual cure of the condition. Some treatments are however available for relieving the symptoms while the immune system suppresses the virus in the body. As a protective measure, patients are usually required to stay at home while they are infectious to avoid spreading the disease to others. Also, sufferers are frequently asked to cut their nails short or to wear gloves to prevent scratching and to minimize the risk of secondary infections.

The condition resolves by itself within a couple of weeks but meanwhile patients must pay attention to their personal hygiene. The rash caused by varicella zoster virus may however last for up to one month, although the infectious stage does not take longer than a week or two.

Although there have been no formal clinical studies evaluating the effectiveness of topical application of calamine lotion, a topical barrier preparation containing zinc oxide and one of the most commonly used interventions, it has an excellent safety profile. It is important to maintain good hygiene and daily cleaning of skin with warm water to avoid secondary bacterial infection. Scratching may also increase the risk of secondary infection.

Acetaminophen (paracetamol) but not aspirin may be used to reduce fever. Aspirin use by someone with chickenpox may cause the serious, sometimes fatal disease of the liver and brain, Reye syndrome. People at risk of developing severe complications who have had significant exposure to the virus may be given intra-muscular varicella zoster immune globulin (VZIG), a preparation containing high titres of antibodies to varicella zoster virus, to ward off the disease.

Antiviral like acyclovir can be used. If oral acyclovir is started within 24 hours of rash onset it decreases symptoms by one day but has no effect on complication rates. Use of acyclovir therefore is not currently recommended for immunocompetent individuals (i.e., otherwise healthy persons without known immunodeficiency or on immunosuppressive medication). Children younger than 12 years old and older than one month are not meant to receive antiviral medication unless they are suffering from another medical condition which would put them at risk of developing complications. Infection in otherwise healthy adults tends to be more severe. Treatment with antiviral drugs (e.g. acyclovir or valacyclovir) is generally advised, as long as it is started within 24–48 hours from rash onset.Remedies to ease the symptoms of chickenpox in adults are basically the same as those used on children. Infection in adults is associated with greater morbidity and mortality due to pneumonia (either direct viral pneumonia or secondary bacterial pneumonia), hepatitis,and encephalitis. In particular, up to 10% of pregnant women with chickenpox develop pneumonia, the severity of which increases with onset later in gestation. Although the risk is higher with herpes zoster. Necrotizing fasciitis is also a rare complication( NF, commonly known as flesh-eating disease or flesh-eating bacteria syndrome, is a rare infection of the deeper layers of skin and subcutaneous tissues, easily spreading across the fascial plane within the subcutaneous tissue,as necrosis of the subcutaneous tissue and fascia with relative sparing of the underlying muscle) During pregnancy the dangers to the fetus associated with a primary VZV infection are greater in the first six months. In the third trimester, the mother is more likely to suffer from the adverse effects of the infection. For pregnant women, antibodies produced as a result of immunization or previous infection are transferred via the placenta to the fetus. Women who are immune to chickenpox cannot become infected and do not need to be concerned about it for themselves or their infant during pregnancy. Varicella infection in pregnant women could lead to viral transmission via the placenta and infection of the fetus. If infection occurs during the first 28 weeks of gestation, this can lead to fetal varicella syndrome (also known as congenital varicella syndrome). Effects on the fetus can range in severity from underdeveloped toes and fingers to severe anal and bladder malformation. Possible problems include:

· Damage to brain: encephalitis, microcephaly, hydrocephaly, aplasia of brain

· Damage to the eye: optic stalk, optic cup, andlens vesicles, microphthalmia, cataracts, chorioretinitis, optic atrophy

· Other neurological disorder: damage to cervical and lumbosacral spinal cord, motor/sensory deficits, absent deep tendon reflexes, anisocoria/Horner's syndrome

·Damage to body: hypoplasia of upper/lower extremities, anal and bladder sphincter dysfunction

·Skin disorders: (cicatricial) skin lesions, hypopigmentation

Infection late in gestation or immediately following birth is referred to as "neonatal varicella". Maternal infection is associated with premature delivery. The risk of the baby developing the disease is greatest following exposure to infection in the period 7 days prior to delivery and up to 7 days following the birth. The baby may also be exposed to the virus via infectious siblings or other contacts, but this is of less concern if the mother is immune. Newborns who develop symptoms are at a high risk of pneumonia and other serious complications of the disease.

Shingles(Herpes zoster)-After a chickenpox infection, the virus remains dormant in the body's nerve tissues. The immune system keeps the virus at bay, but later in life, usually as an adult, it can be reactivated and cause a different form of the viral infection called shingles (scientifically known as herpes zoster). Many adults who have had chickenpox as children are susceptible to shingles as adults, often with the accompanying condition postherpetic neuralgia, a painful condition that makes it difficult to sleep. Even after the shingles rash has gone away, there can be night pain in the area affected by the rash.Shingles affects one in five adults infected with chickenpox as children, especially those who are immune suppressed, particularly from cancer, HIV, or other conditions. However, stress can bring on shingles as well, although scientists are still researching the connection. Shingles are most commonly found in adults over the age of 60 who were diagnosed with chickenpox when they were under the age of 1. .

 

 The chickenpox vaccine is not part of the routine childhood vaccination schedule in the India,the vaccine is currently advisable only to people who are particularly vulnerable to chickenpox. A vaccinated person is likely to have a milder case of chickenpox if infected.