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Varicella in Adult
Other Resources UpToDate PubMed

Varicella in Adult

Contributors: Molly Plovanich MD, Susan Burgin MD
Other Resources UpToDate PubMed


Varicella, also known as chickenpox, is a self-limited viral infection caused by varicella-zoster virus (VZV), a member of the Herpesviridae family. Prior to the clinical implementation of the varicella vaccine, more than 99% of adults aged 40 and older had evidence of previous infection. Transmission occurs via airborne respiratory droplets or direct contact with vesicular fluid. The incubation period ranges from 10-20 days.

VZV is an acute, serious viral infection when it occurs in adults. In adults, a 2- to 3-day prodrome of fever, chills, irritability, headache, and myalgias may occur. However, skin lesions are usually the initial manifestation of the disease: an acute eruption of pruritic, erythematous macules and papules that start on the face, oral mucosa, and scalp and spread to the trunk and extremities. The lesions rapidly evolve into 1- to 3-mm vesicles with clear serous fluid on an erythematous background. The hallmark of chickenpox is the presence of lesions in various stages of development. Older lesions will evolve to form pustules and serous crusts that heal within 10 days of time. Fever is variable, usually less than 38.9°C (102°F), but can be anywhere from normal to 40.6°C (105°F) in severe cases.

The most common complication is secondary infection of lesions with Staphylococcus or beta-hemolytic Streptococcus. The streptococcal infection can progress to necrotizing fasciitis. Varicella pneumonia is more common in adults, can lead to adult respiratory distress syndrome, and has an overall mortality rate between 10% and 30%. According to the US Centers for Disease Control and Prevention (CDC), adults have a 25-fold greater mortality risk compared with children aged 1-4.

Less common complications include purpura fulminans and thrombocytopenia with protein S deficiency, orchitis, hepatitis, uveitis, arthritis, myocarditis, nephritis, macular atrophy, gastrointestinal bleeding, bacterial pneumonia, protein-losing enteropathy, and Reye syndrome. Central nervous system (CNS) complications occur rarely. These include aseptic meningitis, dystonia, myelitis, cerebellar ataxia, Guillain-Barré, and encephalitis. The cerebellar form of encephalitis has a high mortality rate in adults.

One varicella episode usually confers lifelong immunity, although reinfections have been documented.

In vaccinated individuals, "breakthrough varicella" can occur. Illness is usually mild (low fever or no fever, fewer lesions [less than 50], less pruritic, shorter duration, absence of vesicles), although some patients present similar to unvaccinated individuals.

Patients are considered contagious for 2-5 days before the onset of cutaneous lesions and for 6 days after the last crop has appeared.

Prior to the clinical implementation of the varicella vaccine, approximately 100 deaths per year in the United States were attributed to acute varicella. The highest incidence is from March to May.

Immunocompromised Patient Considerations
Pregnant patients may be at increased risk for severe illness from varicella. Maternal varicella in the first 20 weeks of pregnancy is associated with a 2% risk of fetal damage. If maternal varicella occurs near the time of delivery, the neonate is at risk for severe neonatal varicella.

Varicella may be severe in human immunodeficiency virus (HIV)-infected and other immunocompromised individuals (particularly those with lymphoma and those receiving immunosuppressive therapy, including systemic steroid therapy), with a 7%-10% mortality rate. These patients often have a more extensive (disseminated) and atypical eruption (often with purpura and hemorrhagic vesicles) as well as visceral involvement (CNS, lung, liver). HIV-infected patients have a 7-15 times greater risk of developing herpes zoster.


B01.9 – Varicella without complication

38907003 – Varicella

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Differential Diagnosis & Pitfalls

  • Herpes simplex virus (HSV) – Grouped vesicles on an erythematous base. Request direct fluorescence antibody (DFA) testing (DFA HSV, in contrast to DFA VZV) and viral culture. Look for more localized lesions in HSV at site of primary infection.
  • Hand-foot-and-mouth disease (Coxsackie virus) – Look for vesicular eruption of palms and soles.
  • Impetigo – Honey-colored crusts with larger plaques and erosions.
  • Rickettsialpox – Check serologies; transmitted by the mouse mite.
  • Pityriasis lichenoides et varioliformis acuta (PLEVA) – Asymptomatic crops of erythematous papules that spontaneously resolve within weeks and recur at a later time.
  • Bullous drug eruption – Vesicular / bullous lesions. Eosinophilia on CBC and histology are often seen (but not an invariable finding). Look for NSAIDs, sulfonamides, and penicillin medication history.
  • Contact dermatitis – Does not have prodromal symptoms and will be localized to site of contact (in contrast to disseminated distribution seen in VZV).
  • Vasculitis – Check for rheumatoid factors (RF), antinuclear antibodies (ANA), anti-double-stranded DNA, antineutrophil cytoplasmic antibodies (ANCA), cryoglobulins, C3 and C4 levels and clinical course that does not resolve over several weeks.
  • Eczema herpeticum – Hemorrhagic crusted papules and vesicles overlying eczematous skin, usually on the face.
  • Insect bite reactions – Larger papules and vesicles; lesions do not rapidly progress to pustules and crusts; favor exposed sites.
  • Molluscum contagiosum – No viral symptoms; lesions do not rapidly progress to pustules and crusts.
  • Monkeypox
  • Echo virus
  • Variola (smallpox) – All lesions at the same stage; favors extremities. Note: this disease has been eradicated; therefore, it would only be diagnosed in the event of a bioterrorist act.

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Last Updated:05/30/2022
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Patient Information for Varicella in Adult
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Contributors: Medical staff writer


Chickenpox (varicella) is an infectious disease caused by the varicella-zoster virus that goes away on its own. Infection spreads among humans through fluids from the airways, such as from coughing and sneezing, with non-infected household members at high risk of becoming infected as well. The development (incubation) period is 14-16 days, and the first sign of disease is a rash. People are considered contagious for 2-5 days before the onset of skin lesions and for 6 days after the last series of rashes have appeared.

The most common complication is infection of lesions with bacteria. Rare complications include lung infection (pneumonia) or brain infection (encephalitis). Children who have weak immune systems, eczema, or recent sunburns have more severe symptoms. Because the virus remains resting (latent) in the parts of nerves that are near the spinal cord (nerve roots) for life, about 1 in 10 adults will get shingles (zoster) when the virus reappears, usually under conditions of stress to the body.

After having chickenpox, a person is usually immune for life, although reinfection is possible.

Who’s At Risk

Chickenpox occurs most commonly in children under 10. Those under 1 year of age (whose mothers have had chickenpox before) are not usually infected, as they still have some immunity from their mother's antibodies, which were transferred to them before birth.

The chickenpox vaccine has been part of routine childhood vaccinations (at age 12-18 months) since 1995, but many children have still not been vaccinated. About 85% of children who have been vaccinated avoid infection, but even if they do show symptoms, they are generally mild. Most infections occur from March to May.

Signs & Symptoms

Most children act sick with fever and vague symptoms (loss of appetite, headache, belly ache) for 1-2 days before they start to break out with a rash. These symptoms last for 2-4 days after the rash appears.

An early pink-to-red, flat, small spot rapidly becomes bumpy and then blisters with a surrounding halo of redness. The spots usually appear first on the trunk or scalp. Linings of body cavities, such as the mouth or nose (mucous membranes), palms, and soles, can have a few lesions. The average child develops a few hundred blisters, most of which heal without leaving scars. A child who has had the chickenpox vaccine will have far fewer lesions.

The blister is usually described as looking like a dewdrop on a rose petal. The blister area (vesicle) is thin-walled and easily broken. Blisters become cloudy and then crust over, with healing completed within 1-3 weeks. Lesions often occur in 3 or more successive series (crops). Lesions in different stages of development may occur at the same time.

Self-Care Guidelines

Since the illness resolves on its own after 1-3 weeks, it is most important to keep the child comfortable and to discourage scratching, which can cause infection and scars.

For itching:
  • Oatmeal baths in lukewarm water
  • Oral antihistamines (diphenhydramine, chlorpheniramine)
  • Clip the child's fingernails
  • Apply calamine lotion
  • DO NOT USE lotions containing antihistamines or lidocaine, as they are no more effective than the previous measures and might cause allergic reactions later on.
For pain and fever:
  • Use acetaminophen (eg, Tylenol).
  • DO NOT USE aspirin in children aged 18 years or younger, as the use of aspirin in children with chickenpox has been associated with Reye syndrome, a severe disease.
  • The American Academy of Pediatrics recommends AVOIDING treatment with ibuprofen (eg, Advil) if possible because it has been associated with life-threatening bacterial skin infections.
Because chickenpox is highly contagious, keep the child at home and resting until symptoms are gone and all blisters are dried up. Avoid any contact between your child and pregnant individuals who have never had chickenpox, newborns, or people who have a weak immune system or eczema. Once all the blisters have dried up into scabs, the child is not considered contagious to others.

When to Seek Medical Care

Most infections do not require treatment.

If there are adults or teens in the household who have never had chickenpox or people with eczema, asthma, or a weakened immune system, have them contact their doctor, as they may require antiviral medication. This usually needs to be done early (during the first day of the rash).

Call your child's doctor if:
  • He or she has eczema, asthma, or a weakened immune system.
  • The fever lasts more than 4 days or exceeds 102 degrees Fahrenheit.
  • Any rash areas look red, swollen, and leak pus.
  • He or she has a severe cough, vomiting, headache, drowsiness, confusion, stiff neck, trouble looking at bright lights, or difficulty walking or breathing.


Antiviral medication may be given if the child is seen early (during the first day of the rash) for children at higher risk for more severe chickenpox infection (those with asthma, eczema, recent sunburn, children taking aspirin or corticosteroids on a regular basis, and those with weak immune systems).


Bolognia, Jean L., ed. Dermatology, pp.1241-1243. New York: Mosby, 2003.

Freedberg, Irwin M., ed. Fitzpatrick's Dermatology in General Medicine. 6th ed. pp.2070, 2080-2081, 2434-2437. New York: McGraw-Hill, 2003.
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Varicella in Adult
A medical illustration showing key findings of Varicella : Fever, Headache, Malaise, Widespread distribution, Myalgia, Pruritus, Tiny vesicles, Umbilicated vesicles
Clinical image of Varicella - imageId=3703202. Click to open in gallery.  caption: 'A close-up of scattered vesicles, some umbilicated.'
A close-up of scattered vesicles, some umbilicated.
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