Varicella (chickenpox) nursing care: assessment, interventions, and NCLEX review

Varicella (chickenpox) is a highly contagious infection caused by varicella-zoster virus (VZV), a member of the herpesvirus family. Primary infection produces the familiar disseminated vesicular rash of childhood, but the virus never fully clears the body — it establishes lifelong latency in the dorsal root ganglia and can reactivate decades later as herpes zoster (shingles). For nursing students, VZV is a high-yield topic because it tests the full breadth of nursing priorities at once: recognizing the correct isolation tier (airborne plus contact — not just contact), understanding why aspirin is absolutely contraindicated in children with viral illness, knowing which high-risk patients need post-exposure prophylaxis, and identifying the adults at risk for life-threatening complications. This reference covers all of it — pathophysiology through pharmacology — with NCLEX practice at the end.

At-a-glance quick reference

Pathophysiology

Primary infection

VZV enters the body through the respiratory tract or conjunctival mucosa. After initial replication in the nasopharynx, the virus reaches regional lymph nodes and causes a primary viremia around days 4–6 of incubation. The virus then seeds reticuloendothelial cells in the spleen, liver, and lymph nodes, amplifying viral load before a secondary viremia around days 11–20 carries VZV to the skin and mucous membranes. This secondary viremia causes the characteristic disseminated rash and marks the beginning of the patient’s contagious period — which actually starts 1–2 days before visible lesions appear, when respiratory shedding is already underway.

Rash progression

Varicella lesions pass through a predictable sequence: macule → papule → vesicle → pustule → crust. The progression from macule to crust typically takes 24–48 hours per lesion. A defining clinical feature is that lesions appear in successive crops over 3–5 days, meaning multiple stages coexist on the same patient simultaneously — you will see fresh papules appearing next to crusted vesicles. New crops typically begin on the trunk and spread centrifugally to the face, scalp, and extremities. The mucous membranes (oral cavity, pharynx, conjunctiva, vaginal mucosa) are commonly involved.

VZV latency and reactivation

After primary infection, VZV travels retrograde along sensory nerve axons to the dorsal root ganglia, where it establishes lifelong latency without causing symptoms. Reactivation — typically triggered by immunosuppression, aging, or severe stress — produces herpes zoster (shingles), characterized by a painful unilateral vesicular eruption that follows a single dermatome. Unlike primary varicella, zoster lesions are localized rather than disseminated. Zoster can itself infect susceptible contacts, causing primary varicella in those individuals.

Clinical presentation

Prodrome

Adults and older children typically experience a prodromal phase lasting 1–2 days before rash onset, characterized by:

• Fever (38–39°C / 100–102°F)
• Malaise and fatigue
• Headache
• Myalgia
• Anorexia

Young children often have minimal or absent prodrome — the rash may be the first sign.

Characteristic rash

The classic varicella rash is often described as “dewdrops on rose petals” — small, clear vesicles on an erythematous base. Key features nurses must recognize:

• Distribution: Begins on the trunk, spreads to face, scalp, and extremities; relatively spares the palms and soles
• Successive crops: New lesions appear for 3–5 days; all stages present simultaneously (diagnostic)
• Pruritus: Intense itching that begins with the vesicular stage and drives scratching — the main vector for secondary bacterial infection
• Mucous membrane involvement: Shallow ulcers in the oropharynx, pharyngitis, and occasionally genital lesions

Fever and systemic symptoms

Fever typically peaks at the time of maximum rash and resolves as lesions crust. Persistent or spiking fever after the first 3–4 days should raise concern for secondary bacterial superinfection or pneumonia. In immunocompromised patients, the presentation can be more severe, with higher fever, more numerous and hemorrhagic lesions, and prolonged new lesion formation beyond the typical 5-day window.

Breakthrough varicella

Vaccinated individuals who contract varicella (breakthrough disease) typically have a milder illness: fewer than 50 lesions, fewer or no vesicles (predominantly maculopapular), lower fever, and shorter illness duration. They are still contagious until no new lesions have appeared for 24 hours — the crusting criterion does not apply in the same way because lesions may not fully vesiculate.

Isolation precautions

Airborne and contact: why both matter

Varicella requires both airborne and contact precautions — one of the most frequently tested isolation combinations in nursing education. This is because VZV transmits via two distinct routes simultaneously:

1. Airborne route: Aerosolized respiratory particles and dried vesicle fluid remain suspended in air and travel beyond 3 feet. This is why a standard surgical mask is insufficient — staff entering the room require an N95 respirator (or higher).
2. Contact route: Direct contact with vesicle fluid transmits the virus. This requires gloves and gown for all patient contact.

The room must be a negative air-pressure room (at least 12 air changes per hour, air exhausted directly outside or filtered through HEPA). In facilities without negative pressure rooms, the patient is cohorted with other confirmed varicella patients or placed in the most isolated available room with the door closed.

Only immune healthcare workers (documented prior infection or two doses of varicella vaccine) should care for varicella patients. Susceptible staff should be excluded from the room.

Duration of isolation

Maintain airborne and contact precautions until all lesions have dried and crusted. This typically occurs 5–7 days after rash onset in immunocompetent patients but may take significantly longer in immunocompromised patients, who should remain isolated until lesion crusting is confirmed. For breakthrough varicella (vaccinated patients), isolation continues until no new lesions have appeared for 24 hours.

Isolation comparison: varicella vs. other infectious diseases

Understanding where varicella sits in the isolation hierarchy is essential for NCLEX.

The key differentiator for NCLEX: varicella and disseminated zoster require airborne precautions in addition to contact. Influenza and meningococcal disease require only droplet. MRSA and C. difficile require only contact.

Nursing assessment

Lesion staging and skin evaluation

Begin with a systematic head-to-toe skin assessment (see wound assessment guide for general lesion documentation principles). Document:

• Total estimated number of lesions
• Distribution (trunk-dominant vs. spread to extremities)
• Stages present (macule, papule, vesicle, pustule, crust — all stages present simultaneously is characteristic)
• Evidence of scratching: excoriation, broken lesion surfaces, erythema or warmth suggesting secondary bacterial infection
• Mucous membrane involvement (oropharyngeal inspection)

Check fingernails for length — long nails dramatically increase secondary infection risk.

Respiratory assessment

Assess for signs of varicella pneumonia, particularly in adults, smokers, pregnant women, and immunocompromised patients:

• Respiratory rate and effort
• Oxygen saturation (SpO₂)
• Cough — dry initially; productive or blood-tinged with pneumonia
• Chest auscultation: crackles, decreased breath sounds
• Dyspnea or pleuritic chest pain

Varicella pneumonia typically develops 1–6 days after rash onset and can progress rapidly to respiratory failure requiring mechanical ventilation.

Neurological assessment

Assess for CNS involvement:

• Level of consciousness and orientation
• Coordination and gait — cerebellar ataxia presents as ataxia, nystagmus, and dysarthria and is more common in children
• Signs of encephalitis: altered mental status, seizures, severe headache, photophobia
• Assess pediatric patients for behavioral changes, irritability, and vomiting

Hepatic and laboratory findings

Monitor liver function in symptomatic patients or those on antivirals:

• Serum AST, ALT (elevations common with varicella hepatitis)
• CBC: lymphocytosis typical; monitor for secondary bacterial infection (elevated WBC with left shift)
• BMP: electrolytes and renal function if IV acyclovir is used (nephrotoxic — requires adequate hydration)

For lab reference ranges, see the nursing lab values cheat sheet.

Complications

Reye’s syndrome: the critical nursing Pearl

Reye’s syndrome warrants special emphasis because it is heavily tested and the mechanism is important to understand. It is characterized by:

• Acute non-inflammatory encephalopathy (cerebral edema without meningeal inflammation)
• Hepatic steatosis and dysfunction
• Hyperammonemia
• Hypoglycemia (particularly in younger children)

The syndrome follows viral illness — varicella and influenza are the two most strongly associated viruses — when aspirin (salicylate) is given to children or adolescents. The exact mechanism is not fully established, but salicylates appear to impair mitochondrial function in the setting of viral infection, leading to fatty acid oxidation failure and energy failure in the liver and brain. Onset is typically within days of starting aspirin: vomiting is followed by rapidly progressive encephalopathy.

Nursing action: Educate all parents and guardians of pediatric patients that aspirin and aspirin-containing products are contraindicated in children under 18 years of age with any viral illness. Ibuprofen is also not recommended by the CDC for varicella due to its association with serious bacterial skin infections. Acetaminophen is the antipyretic of choice.

Nursing interventions

Pharmacology

Antiviral therapy

Mechanism of action

Acyclovir and valacyclovir are both nucleoside analogs that inhibit viral DNA polymerase. The mechanism is highly selective for virus-infected cells:

1. VZV-infected cells contain viral thymidine kinase, which phosphorylates acyclovir to acyclovir monophosphate
2. Host cell kinases further phosphorylate it to acyclovir triphosphate
3. Acyclovir triphosphate competitively inhibits the viral DNA polymerase and acts as a chain terminator when incorporated into the growing viral DNA strand
4. Human DNA polymerase has very low affinity for acyclovir triphosphate, which explains the favorable safety profile

Because the first phosphorylation step requires viral thymidine kinase, the drug is selectively active in infected cells. Acyclovir resistance arises primarily through mutations in the viral thymidine kinase gene and is most clinically relevant in immunocompromised patients on prolonged therapy.

Varicella vaccine

The varicella vaccine (Varivax) is a live attenuated vaccine given as a 2-dose series — first dose at 12–15 months, second at 4–6 years. One dose provides approximately 85% protection; two doses provide 98–99% protection against any varicella and approximately 100% protection against severe disease.

Contraindications:

• Active immunocompromised states (HIV with low CD4 count, high-dose corticosteroids, chemotherapy, bone marrow transplant)
• Pregnancy — the live virus poses theoretical teratogenic risk; vaccinate post-partum
• Allergy to gelatin or neomycin
• Recent blood product or immunoglobulin administration (delays vaccine due to antibody interference — VariZIG delays vaccination by at least 5 months)

Special populations

Pregnancy

Varicella in pregnancy carries risks for both mother and fetus. The mother is at significantly higher risk for varicella pneumonia (up to 40% of pregnant women with varicella develop pneumonia, compared to 10–20% in non-pregnant adults), and mortality from varicella pneumonia is elevated in pregnancy. Maternal infection in the first 20 weeks of gestation carries approximately a 2% risk of congenital varicella syndrome, characterized by limb hypoplasia, cicatricial skin scarring following dermatomal distribution, chorioretinitis, cortical brain atrophy, and low birthweight. Maternal infection near delivery (5 days before to 2 days after) creates neonatal varicella risk because the infant has not received passive antibody transfer.

Antiviral therapy with oral acyclovir is generally recommended for pregnant women with varicella. Susceptible pregnant women exposed to varicella should receive VariZIG within 96 hours.

Neonates

Neonates born to mothers with peripartum varicella (onset 5 days before to 2 days after delivery) are at highest risk for severe disseminated disease because they lack transplacental VZV antibodies. Without treatment, neonatal varicella carries a mortality rate of approximately 30%. These neonates should receive VariZIG at birth if maternal infection onset is within the risk window and IV acyclovir if they develop active disease.

Immunocompromised patients

Immunocompromised patients — including those on high-dose corticosteroids, chemotherapy, biologic agents (particularly TNF inhibitors), or with HIV/AIDS — are at risk for:

• Severe primary varicella with disseminated skin involvement (>300 lesions)
• Prolonged illness with continued new lesion formation
• Visceral dissemination (pneumonia, hepatitis, encephalitis)
• VZV retinitis (rare but potentially blinding)
• Acyclovir-resistant VZV (especially in prolonged treatment)

These patients require IV acyclovir therapy, close monitoring, and extended isolation until complete lesion crusting.

Adults versus children

Adults without prior varicella immunity who acquire primary infection face substantially higher complication rates than children. Varicella pneumonia, encephalitis, and hepatitis all occur at higher frequency and severity in adults. Adults are also more likely to develop postherpetic complications from eventual zoster reactivation. Adults aged 13 and older who have no evidence of varicella immunity should receive the 2-dose varicella vaccine series.

NCLEX practice questions

Question 1

A nurse is caring for a 7-year-old child hospitalized with active varicella. Which personal protective equipment (PPE) is required before entering the room?

A. Surgical mask and gloves only B. N95 respirator, gown, and gloves C. Gown and gloves only D. Surgical mask, gown, and gloves

Answer: B

Rationale: Varicella requires both airborne and contact precautions. Airborne precautions mandate an N95 respirator (not a surgical mask) because VZV travels via aerosolized particles that remain airborne beyond 3 feet. Contact precautions require gown and gloves. A surgical mask is insufficient.

Question 2

The parent of a 5-year-old with varicella asks if they can give ibuprofen for fever. The nurse’s best response is:

A. “Ibuprofen is fine for fever — it works better than acetaminophen.” B. “Either ibuprofen or aspirin is safe for children with chickenpox.” C. “Use acetaminophen only. Aspirin is linked to Reye’s syndrome, and ibuprofen is also not recommended with varicella.” D. “Ibuprofen is preferred because it also reduces inflammation from the rash.”

Answer: C

Rationale: Aspirin is absolutely contraindicated in children with varicella due to the risk of Reye’s syndrome — a life-threatening acute encephalopathy and hepatic failure. The CDC also advises against ibuprofen in varicella due to its association with invasive bacterial skin infections. Acetaminophen is the only recommended antipyretic.

Question 3

A 28-year-old immunocompromised patient receiving chemotherapy is exposed to a family member with active varicella. The patient has no history of chickenpox and has never been vaccinated. Which action is the highest priority?

A. Administer the varicella vaccine immediately B. Administer VariZIG intramuscularly within 96 hours of exposure C. Begin prophylactic oral acyclovir and monitor for symptoms D. No intervention is needed unless symptoms develop

Answer: B

Rationale: VariZIG (varicella-zoster immune globulin) is indicated for post-exposure prophylaxis in susceptible immunocompromised patients. It must be administered within 96 hours of exposure. The live varicella vaccine is contraindicated in immunocompromised patients because the live attenuated virus could cause disseminated infection in a patient without adequate immune function.

Question 4

A nurse is planning discharge for a child with varicella. Which assessment finding indicates the child is no longer contagious and safe for discharge?

A. The child has been afebrile for 24 hours B. No new vesicles have appeared in the past 12 hours C. All skin lesions have dried and formed crusts D. The rash has been present for 7 days

Answer: C

Rationale: The infectious period for varicella ends when all lesions have dried and crusted over — this is the CDC criterion for ending isolation. Fever resolution, a 12-hour window without new vesicles, or the passage of 7 days do not confirm that the patient is non-infectious if any lesions remain open or vesicular.

Question 5

A pregnant woman in the first trimester is diagnosed with varicella infection acquired at 12 weeks gestation. The nurse understands that the greatest fetal risk is:

A. Preterm labor and premature rupture of membranes B. Congenital varicella syndrome, with limb defects and cicatricial skin scarring C. Neonatal varicella at birth due to perinatal transmission D. Intrauterine growth restriction from maternal fever alone

Answer: B

Rationale: Maternal varicella infection before 20 weeks of gestation carries approximately a 2% risk of congenital varicella syndrome, characterized by limb hypoplasia, dermatomal cicatricial skin scarring, chorioretinitis, and cortical brain anomalies. Neonatal varicella (answer C) is the risk when maternal infection occurs near the time of delivery (5 days before to 2 days after), not during the first trimester.

Question 6

A nurse is preparing to administer acyclovir 800 mg orally to an adult patient with varicella who developed a rash 4 days ago. The patient asks, “Will this medicine make my chickenpox go away faster?” The most accurate response is:

A. “Yes, acyclovir will eliminate the virus completely and prevent recurrence.” B. “Acyclovir works best when started within 72 hours of the rash — starting now may provide limited benefit.” C. “Acyclovir is not effective after day 2 and should be discontinued.” D. “This medication prevents varicella pneumonia but will not affect your rash.”

Answer: B

Rationale: Acyclovir is most effective when initiated within 24–72 hours of rash onset because viral replication is highest in this window. Starting at day 4 is outside the optimal window and provides limited benefit in otherwise healthy adults. The nurse should administer as ordered while accurately setting patient expectations. Acyclovir does not eradicate latent VZV from the dorsal root ganglia and does not prevent future zoster reactivation.

Related resources

• Meningococcal meningitis nursing — droplet-only isolation: compare the precaution tier to varicella’s airborne + contact requirement
• MRSA nursing — contact precautions only; secondary bacterial skin infection risk
• Wound assessment nursing — systematic skin lesion documentation principles
• Sepsis nursing — secondary bacterial sepsis as a complication of superinfected varicella lesions
• Influenza nursing — droplet precautions comparison; Reye’s syndrome shared aspirin risk
• Nursing lab values cheat sheet — hepatic enzyme and CBC reference ranges for monitoring varicella complications