Varicella (Chickenpox)
B. Denise Hemby and Theresa M. Campo
Definition
Varicella, commonly called chickenpox, is a viral disease that largely occurs during childhood with 90% occurring in children younger than 10 years. Chickenpox that affects healthy
children is a self-limiting illness. Morbidity is associated with adults and immunocompromised individuals. Manifestation is characterized as generalized, pruritic, vesicular rash. Varicella zoster virus (VZV) remains dormant in the sensory nerve roots for life. Adults may have a more complicated course than children with more widespread rash, prolonged fever, and increased risk of complications like varicella pneumonia.
A.VZV (shingles) is the reactivation of the virus and the risk increases with age. The symptoms include pain, vesicular rash, sensory loss, and neurologic complications. Diagnostic clues are sensory symptoms: Pain and vesicular rash that do not cross midline. Postherpetic neuralgia (PHN) is a prolonged complication.
B.Pregnant women who get VZV are at an increased risk for serious complications. If contracted during the first or early third trimester, the baby has a risk (0.4%–2.0%) of being born with congenital varicella syndrome, scarring on the skin, abnormalities in limbs, brain, eyes, and low birth weight.
Incidence
In 1995, the vaccine for varicella was introduced and since then the incidence has significantly declined. As of November 2016, according to the Centers for Disease Control and Prevention (CDC), VZV causes about four million cases, 10,600 hospitalizations, and 100 to 150 deaths each year.
Pathogenesis
A.VZV, herpesvirus 3, is a member of the herpesvirus family. Humans are the only source of infection for this highly contagious virus. Person-to-person transmission occurs primarily by direct contact with a patient with varicella or zoster, by airborne droplet, from respiratory secretions, and from direct contact with vesicular zoster lesions. In utero infections also occur from transplacental passage of the virus during maternal varicella infection.
B.The incubation period lasts 10 to 21 days. It is communicable 1 to 2 days to 1 week before onset of macular rash and the patient remains infectious for 4 to 5 days after lesions crust over (about 1 week). It takes from 10 to 21 days after exposure for someone to develop varicella.
Predisposing Factors
A.Exposure to someone with the varicella virus:
1.Direct contact with skin lesions or by respiratory tract secretions.
2.Direct contact with patients with shingles can induce chickenpox in susceptible healthcare workers.
B.Compromised immune system.
Common Complaints
A.The triad of rash, malaise, and low-grade fever can signal disease onset:
1.Skin lesions or rash: Characteristic rash is pruritic, vesicular exanthem occurring in crops that begin on the head and neck and progress to involve the trunk and extremities. Blisters collapse within 24 hours to 1 week and crust over to form scabs. Skin eruptions appear almost anywhere on the body, including the scalp, penis, and inside the mouth, nose, throat, and vagina.
B.Itching.
C.Nausea.
D.Anorexia.
E.Headache.
Other Signs and Symptoms
A.Adults may develop varicella pneumonia. (The risk of pneumonia is higher in smokers than nonsmokers.)
B.Cough.
C.Headache.
D.Respiratory symptoms: Cough and chest discomfort. Respiratory symptoms usually develop shortly after cutaneous eruption. Respiratory failure in pregnancy can be rapid.
E.Abdominal pain lasting 1 to 2 days.
Subjective Data
A.Review the onset, duration, and course of symptoms.
B.Elicit exposure information when noting characteristic rash, the time it started, spread of the rash or lesions, and characteristic changes.
C.Review any pulmonary or nervous system problems, such as seizures, that occur as complications.
D.Determine if the person has HIV, is immunocompromised, or is pregnant.
E.Determine the caregiver’s immunity status to varicella.
F.Review the patient’s immunization history.
G.Review all medications, including over-the-counter (OTC) and herbal products.
Physical Examination
A.Check temperature, pulse, respirations, and blood pressure.
B.Inspect:
1.Conduct a dermal exam, especially the hairline.
2.Inspect the buccal mucosa.
3.Conduct an ear, nose, and throat exam, and a detailed eye exam.
C.Auscultate: Auscultate the heart and lungs.
D.Palpate: Palpate the neck and lymph nodes.
Diagnostic Tests
Diagnosis is usually determined by the appearance of the skin eruptions, and laboratory tests are not necessary. Lab testing is recommended to confirm varicella as a cause, determine susceptibility, establish an individual’s immunity, or establish varicella as cause of death.
A.ELISA is used to determine if a person has antibodies to VZV from past infection or vaccinations.
B.Varicella immunoglobulin G (IgG) and immunoglobulin M (IgM):
1.IgG antibodies help identify nonimmunity.
2.IgM antibodies suggest acute or recent infection.
3.+ IgG with –IgM indicates immunity from either vaccination or past infection.
4.– IgG with –IgM indicates no immunity.
C.Pregnancy test if indicated.
D.Tzanck smear if diagnosis is questionable; it has about 60% sensitivity.
E.Culture lesion for herpes simplex.
F.Chest x-ray experiencing pulmonary symptoms, to rule out pneumonia.
Differential Diagnoses
A.Varicella (chickenpox).
B.Herpes simplex.
C.Viral exanthems.
D.Scabies.
E.Impetigo.
F.Coxsackievirus.
G.Drug reaction.
H.Secondary syphilis.
I.Measles.
J.Rubella.
K.Rocky Mountain spotted fever (RMSF).
Plan
A.General interventions:
1.Avoid contact with persons infected with chickenpox. Patients with varicella should avoid contact with others. Healthcare workers should be immune to varicella.
2.Strict isolation should be enforced. Varicella is contagious 1 week before outbreak and until the lesions crust over (about 1 week). Isolation is a precaution until the vesicles dry.
3.Order oatmeal baths (Aveeno) for comfort. Spray starch may also be sprayed on lesions to assist with severe itching.
B.Patient teaching:
1.Lesions that can be covered pose little risk to a susceptible person because transmission usually occurs from direct contact with the fluid from the lesion. Clothing or a dressing should cover lesions until they have crusted.
2.Scarring can occur from secondary infection of lesions; encourage good handwashing and no scratching.
C.Pharmaceutical therapy:
1.The goal is to reduce morbidity and prevent complications. Treatment is based on age, immune state, duration, and presentation. Three medications can help decrease pain and symptoms, but caution should be taken with altered renal function.
2.Acyclovir (Zovirax). Dosage forms and strengths: intramuscular (IM) 50 mg/mL; suspension 200 mg/5 mL; tablet 400 mg and 800 mg:
a.Varicella zoster—adults greater than 40 kg: 800 mg PO q6h for 5 days; 10 to 15 mg/kg intravenous (IV) q8h for 7 to 10 days.
b.Herpes zoster—adults 800 mg PO q4h for 7 to 10 days.
3.Valacyclovir (Valtrex). Dosage forms and strengths: Tablet 500 mg and 1 g. Herpes zoster—1 g PO q8h for 7 days:
a.Varicella zoster—older than 2 years: 20 mg/kg PO q8h x 5 days (not to exceed 1 g PO q8h).
b.Herpes zoster—1 g PO q8h for 7 to 10 days.
4.Famiciclovir (Famvir). Dosage forms and strengths: Tablet 125, 250, 500 mg:
a.Herpes zoster—adults 500 mg PO q8h for 7 days.
D.Antihistamines and antipyretics are helpful in the symptomatic treatment of pruritus. Diphenhydramine HCL (Benadryl). Adult dosage 25 to 50 mg PO every 4 to 6 hours.
E.The use of corticosteroids for patients with shingles to prevent PHN is controversial.
F.Treatment for PHN includes gabapentin, pregabalin, tricyclic antidepressants, phenytoin, carbamazepine, cimetidine, and topical capsaicin.
G.Immunizations:
1.New shingles recombinant zoster vaccine Shingrix® was Food and Drug Administration (FDA) approved in 2017. CDC recommended healthy adults ≥50 years of age may receive two doses 2 to 6 months apart. Shingrix provides patients with protection against PHN and shingles. Protection remains above 85% the first 4 years postvaccination.
2.Studies revealed that Shingrix was 97% effective in shingles prevention for older adults 50 to 69 years; and 91% prevention-effective among adults ≥70 years old. In comparison, Zostavax® reduced the risk of shingles by 51% for patients ≥50 years old.
3.Zostavax® is a live zoster vaccine approved in 2006 and may be used in healthy adults ≥50 years old who choose this vaccine or are allergic to Shingrix. It is a one-time dose and lasts only 5 years. The greatest risk for shingles and its complications generally occurs after 60 years of age. It is recommended to implement Zostavax in patients ≥65 years. Discuss the risks and benefits with patients that are 50 through 59 years old that are seeking to choose Zostavax rather than Shingrix.
Follow-Up
A.No follow-up is necessary in uncomplicated cases.
B.Have the patient return to the office for any secondary skin infections, conjunctival involvement, central nervous system (CNS) problems such as encephalitis and meningitis, or pneumonia.
Consultation/Referral
A.Refer the patient to a physician if pregnant; varicella pneumonia in pregnancy is a medical emergency.
Individual Considerations
A.Pregnancy:
1.Varicella vaccine should not be administered to pregnant women:
a.Women are advised not to get pregnant for at least 1 month following the varicella immunization.
b.A pregnant mother or household member is not a contraindication for immunization for a child in the household.
2.Reporting of inadvertent immunization when the varicella-zoster-containing vaccine is given during pregnancy is encouraged 1-800-986-8999 or via at www.merckpregnancyregistries.com/varivax.html.
3.Maternal complications of active varicella infection may include preterm labor, encephalitis, and varicella pneumonia. The mortality rate in gravid females is 10%. The profound maternal hypoxia that occurs in varicella pneumonia is associated with increased risk of spontaneous abortion and stillbirth.
4.Fetal complications of active varicella infection may include intrauterine growth restriction (IUGR), limb reduction defects, and eye defects.
5.Acyclovir is a category B drug based on FDA drug classification in pregnancy. IV acyclovir is recommended for the pregnant patient with serious complications of varicella.
B.Adults:
1.Shingles (reactivated chickenpox) appears as grouped vesicular lesions distributed in one to three sensory dermatomes, sometimes accompanied by pain localized to the area. Systemic symptoms are few.
2.A recommendation for varicella vaccination includes persons at high risk for exposure, which include adolescents and adults who live in households with children.
3.Immunocompromised: IV antiviral therapy is recommended for immunocompromised patients, including patients being treated with chronic corticosteroids. Therapy initiated early in the course of illness, especially within 24 hours of rash onset, maximizes efficacy.
C.Geriatrics:
1.Herpes zoster incidence increases with age and clinicians must encourage vaccines to geriatric populations. Studies indicate that older populations experience herpes zoster incidences four times more than patients ≤29 years of age.
2.The thoracic and lumbosacral areas are more prominent locations for a shingles outbreak with geriatric females than geriatric males and the trigeminal area increased in both older adult genders.