Content Reviewers:Antonella Melani, MD, Lisa Miklush, PhD, RNC, CNS, Jodi Berndt, PhD, RN, CCRN-K, PCCN-K, CNE, CHSE, Gabrielle Proper, RN, BScN, MN
15-month-old Lillian Becker presents with a vesicular rash to her trunk and arms, itchiness, and fever. Onset of symptoms occurred after being picked up from daycare 2 days ago.
After being brought in to the pediatric clinic by her father, Ray, Lillian is diagnosed with chickenpox. Varicella, more commonly referred to as chickenpox, is an infectious disease caused by the varicella-zoster virus, or VZV for short, also known as human herpesvirus 3 or HHV-3 for short.
This is a highly contagious airborne virus, meaning it’s transmitted from person to person through respiratory droplets; for example, when a person sneezes or coughs.
But the virus can also be transmitted by direct contact with the skin or oral mucosa of an infected person. Because of that, an important risk factor for varicella involves going to crowded or poorly ventilated public places, such as day-care centers, as well as being immunocompromised.
Now, once a person inhales the virus-containing droplets, these travel down the respiratory mucosa, and the virus starts replicating in the epithelial cells. This is called the incubation period, where the client is asymptomatic, and lasts 14 to 21 days.
Then, the virus gets picked up by nearby immune cells and gets transported to a nearby lymph node, so the client may start to experience prodromal symptoms, such as fever, headache, and malaise.
Prodromal symptoms are more likely in clients over the age of 10, and more severe in adults. About 36 to 48 hours later, the immune cells reach the skin and release the virus. At this point, clients typically develop skin lesions, usually involving the scalp, face, and trunk.
Initially, skin lesions appear as flat, red, and very itchy spots called macules. Over time, macules become elevated and progress into papules, and then into small fluid-filled vesicles.
Within 1 to 2 days, these vesicles begin to crust over and form scabs. After 5 days the scabs fall off, typically without leaving a scar, unless the client picks or scratches their skin.
Now, every 3 to 5 days, new crops of lesions form in different places on the body, so it’s possible to see skin changes in different phases at the same time. Additionally, clients might present with painful sores on mucosal membranes, like inside the mouth.
Finally, it’s important to note that these clients are contagious from 1 to 2 days before skin rash until all lesions have crusted. Now, most clients have chickenpox only once, and will develop immunity against it for the rest of their lives.
However, varicella zoster virus also infects sensory neurons in the skin, and travels backward, or retrogradely, through the neuron to the dorsal root ganglia and trigeminal ganglion.
Later on, if the immune system weakens, due to aging, stress, or immunosuppressive therapy, the virus can be reactivated and travel back up, or anterogradely, through the sensory nerve to the skin, causing an infection in the innervated dermatome that’s called herpes zoster or shingles.
Now, with both chickenpox and shingles can cause some serious complications. The most common one is a secondary bacterial infection of the skin lesions, causing cellulitis.
Other complications include hepatitis, myocarditis, and pneumonia; as well as hemorrhagic complications, such as febrile purpura. Purpura refers to the discoloration of the skin and mucous membranes due to small blood vessel hemorrhage.
Finally, chickenpox can affect the central nervous system. First, it can cause acute post-infectious cerebellar ataxia, which refers to a sudden onset of ataxia following a viral infection.
It can also cause meningitis or inflammation of the meninges; and transverse myelitis, or inflammation of the spinal cord. Finally, children treated with aspirin may develop Reye syndrome, which is characterized by hepatic encephalopathy.
Now, diagnosis of chickenpox is usually based on clinical findings, and can be confirmed using PCR to detect viral DNA. In addition, a Tzanck test or smear, can be performed by scraping a skin lesion to look for multinucleated giant cells in the fluid of the vesicles.
Treatment of chickenpox includes cool baths or calamine lotions to help reduce the itching. Also, analgesics and anti-inflammatory medications can help reduce the fever, but aspirin shouldn’t be used in someone with chickenpox, because it can trigger Reye syndrome.
In addition, clients aged 12 or over can be treated with oral antiviral medications like valacyclovir or famciclovir. On the flip side, immunocompromised clients and those at risk of developing severe disease require intravenous administration of acyclovir.