Chicken pox disease affects 140 million people globally with chicken pox symptoms. Learn about chicken pox stages and treatment from physicians at Meri Sehat.

Chickenpox

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Ismail Munir

Overview

Also called varicella, chickenpox is a highly contagious disease that commonly spreads via respiratory droplets. According to the World Health Organization (WHO), 140 million global cases of infection are recorded every year<a href="#accordion">[1]</a>. More than 90% of the cases occur in children, while less than 5% are in adults<a href="#accordion">[1]</a>. However, the disease is often more severe in adults than in children.

Chickenpox is commonly present in temperate and tropical climates with cases peaking during the spring and winter seasons<a href="#accordion">[1]</a>. In Pakistan, the most recent varicella outbreak occurred between March and May; infected more than 300 people and claimed dozens of lives<a href="#accordion">[2]</a>. The true incidence of chickenpox in Pakistan remains unknown.&nbsp;

Caused by an infection with the varicella-zoster virus (VZV), chickenpox presents with characteristic itchy blisters all over the body. Although a self-limiting disease, in immunocompromised individuals and pregnant women, the infection can result in complications and even death.&nbsp;

Varicella infection usually results in lifetime immunity. However, after recovery, the infectious agent remains latent in the neural ganglia. And in 10-20% of cases, the virus reactivates to cause herpes zoster or shingles<a href="#accordion">[3]</a>. This mostly occurs in those older than 50 years of age or immunocompromised individuals.&nbsp;

Although once a common childhood infection, varicella cases have significantly declined since the development of the chickenpox vaccine in the 1990s. In the United States, routine varicella vaccines caused a 90% reduction in cases among infants from 1995 to 2008<a href="#accordion">[4]</a>. 
&nbsp;

Signs And Symptoms

The disease has an incubation period of 10-21 days. After this, the person develops a characteristic itchy rash that begins as a red or pink bump. While the rash can appear all over the body, it typically first appears on the trunk, face, and then back. Later, it spreads to the trunk and other extremities. These tiny bumps soon develop into fluid-filled blisters that often leak. Eventually, these blisters crust, scab, and fall off.&nbsp;

A person may have bumps all over the body in different phases. Until all blisters have scabbed over, the person is considered contagious. It can take anywhere between 7-14 days for the rash to completely disappear.&nbsp;

Before the rash, individuals may experience the following symptoms: 
&nbsp;

<ul>
	<li>Fever</li>
	<li>Malaise</li>
	<li><a href="https://merisehat.pk/disease/migraines-73">Headache</a></li>
	<li>Nausea</li>
	<li>Loss of appetite</li>
	<li>Abdominal pain 
	&nbsp;</li>
</ul>

Causes

Varicella-zoster virus is a highly transmissible infectious agent that enters the body through the respiratory tract or conjunctiva. It then multiplies in the lungs and after infection travels to the neural ganglia where it can remain dormant for decades. Human-to-human transmission occurs either through inhalation of respiratory droplets or through direct contact with the blisters themselves. 
&nbsp;

Diagnosis

Typically, chickenpox is diagnosed based on the appearance of the rash. The presence of the rash in various phases and a history of exposure to an infected individual are often enough to point to a diagnosis. However, doctors may conduct additional laboratory tests on a patient&#39;s blood, saliva, vesicular fluid, or other specimens to confirm the diagnosis. Mostly, these tests are reserved for confirming suspected cases, unusual cases, or determining a person&#39;s susceptibility to the virus.&nbsp;

The following are the most widely used laboratory tests for diagnosing chickenpox:&nbsp;&nbsp; 
&nbsp;

<ul>
	<li>Polymerase Chain Reaction (PCR):&nbsp;PCR allows researchers to detect VZV DNA in samples of the infected person&#39;s skin lesions. It is the most accurate detection method for chickenpox.&nbsp;</li>
	<li>Antibody Test:&nbsp;Blood levels of IgM and IgG antibodies help determine whether the person has an active infection (IgM) or immunity from a previous infection or vaccine (IgG). However, antibody levels cannot differentiate between a primary infection, a re-infection, or a re-activation of the dormant virus. Doctors often employ the test in pregnant women for determining the need for a pre-treatment varicella vaccine before administering immunosuppressive drugs.&nbsp;</li>
	<li>Vesicle Fluid Culture:&nbsp;Although accurate, this test is extremely time-consuming; therefore, it&#39;s not frequently performed.&nbsp;</li>
	<li>Tzanck Smear:&nbsp;This rapid test looks for giant multinucleated Tzanck cells within smears of vesicular fluid.&nbsp; 
	&nbsp;</li>
</ul>

In pregnant women, doctors often perform an ultrasound to check for fetal abnormalities associated with maternal varicella infection. The scan is typically conducted 5 weeks after the maternal infection. 
&nbsp;

Treatment

There is no specific treatment for chickenpox; instead, management is aimed at relieving the symptoms. This includes warm baths, oral antihistamines, and calamine lotion. Most people are advised rest and to let the disease pass its course. Children and adults are required to stay home until they are no longer contagious.&nbsp;

However, immunocompromised individuals and those at risk of complications can receive intravenous antivirals, such as acyclovir. If the antiviral is given within 24 hours of the rash, it can significantly lessen the severity of chickenpox. Moreover, people at high risk of varicella and those suffering from complications can also receive post-exposure prophylaxis with varicella immunoglobulins. However, these are often costly and not easily available.&nbsp; 
&nbsp;

<h4>Varicella Vaccine</h4>

Prevention is key in controlling the spread of highly contagious infections. The varicella vaccine has played a key role in reducing the number of cases around the world. It is currently available as a monovalent vaccine (varicella only) or in combination with the MMR vaccine, which is for measles, mumps, and rubella. Both contain the live attenuated virus strain.&nbsp;

The first dose is administered to children, who have never had chickenpox, at the age of 12 to 15 months. A second dose is typically administered at 4 to 6 years of age. Unvaccinated children, who are 13 years or older, can be given the two doses, 28 days apart. Moreover, unvaccinated adults are also administered one or two doses of the vaccine after consultation with their doctor.&nbsp;&nbsp; 
&nbsp;

The disease is mostly self-limiting. However, in neonates, pregnant women, and immunocompromised individuals, the disease can result in several complications. Common complications include dehydration, exacerbation of asthma, and scarring from the healed skin lesions. In some cases, chickenpox can also result in life-threatening complications. These include: 
&nbsp;

<ul dir="ltr">
	<li>Secondary Bacterial Infection:&nbsp;This is the most common complication in children and commonly affects the skin, joints, or muscles<a href="#accordion">[1]</a>. Most skin lesions result from scratching the rash which gives entry to bacteria, such as streptococci and staphylococci. Cellulitis, impetigo, and necrotizing fasciitis are some of the common manifestations of a secondary bacterial infection.&nbsp;&nbsp;</li>
</ul>

&nbsp;

<ul dir="ltr">
	<li><a href="https://merisehat.pk/disease/pneumonia">Pneumonia</a>:&nbsp;Viral pneumonia is the most common complication in adults<a href="#accordion">[1]</a>. Symptoms include fever, cough, and difficulty in breathing.&nbsp;</li>
</ul>

&nbsp;

<ul dir="ltr">
	<li>Neurological Complications:&nbsp;Neurological complications are extremely rare and mostly present as encephalitis or cerebellar ataxia. Patients may present with dizziness, headache, and seizures.&nbsp;</li>
</ul>

&nbsp;

<ul dir="ltr">
	<li>Hemorrhagic Complications:&nbsp;Immunocompromised individuals may develop hemorrhagic complications, such as thrombocytopenia and purpura.&nbsp;</li>
</ul>

&nbsp;

<ul dir="ltr">
	<li>Congenital Varicella Syndrome:&nbsp;In neonates, a varicella infection is often fatal. Congenital varicella syndrome develops in 0.4-0.2% of fetuses born to mothers infected 5 days before delivery or 2 days after it<a href="#accordion">[1]</a>. The neonate can have a low birth weight and develop abnormalities of the eyes, limbs, and brain.&nbsp;</li>
</ul>

&nbsp;

<ul dir="ltr">
	<li>Shingles:&nbsp;Re-activation of the VZV from its dormant phase in the neural ganglia results in a herpes zoster infection called shingles. This is more common in older adults and immunocompromised individuals.&nbsp; 
	&nbsp;</li>
</ul>

While it is not always possible to predict the course of infection, looking out for the following warning signs can help prevent the development of severe complications:&nbsp;

<ul>
	<li>Rash spreading to the eyes</li>
	<li>Development of dizziness or shortness of breath</li>
	<li>Rash becomes tender, warm, and red 
	&nbsp;</li>
</ul>

Key Points

<ul>
	<li>Chickenpox is a highly infectious disease caused by an infection with the varicella-zoster virus. The virus typically spreads via inhalation of respiratory droplets from an infected individual.</li>
	<li>Approximately 10-21 days after exposure, people develop the characteristic rash that starts from the chest and face. The rash is itchy and consists of fluid-filled blisters that leak, scab, and then fall off. Before the rash, individuals might experience fever, headache, malaise, and loss of appetite.&nbsp;</li>
	<li>Doctors rely on a history of exposure to an infected person and the characteristic rash for diagnosis. Laboratory tests, such as PCR and antibody levels, might also be conducted.</li>
	<li>Although there is no specific treatment for chickenpox, doctors often prescribe antivirals to immunocompromised patients.</li>
	<li>The varicella vaccine contains a live attenuated virus and provides 90% protection against infections. It can be administered as a two-dose regimen in both children and unvaccinated adults at risk of infection. 
	&nbsp;</li>
</ul>

[1] WHO, 2014. Varicella and herpes zoster vaccination position paper., Geneva: s.n.

[2] Yousaf, M. Z. et al., 2018. Deadly outbreak of chickenpox at district Faisalabad, Pakistan: possible causes, and preventive way forward. Molecular Biology Reports.

[3] WHO, n.d. Varicella. [Online]

[4] Chaves, S. S. et al., 2011. Varicella in infants after implementation of the US varicella vaccination program. Pediatrics, 128(6), pp. 1071-7.

[5] Aebi, C., Ahmed, A. & Ramilo, O., 1996. Bacterial complications of primary varicella in children. Clinical Infectious Diseases, 23(4), pp. 698-705.

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