History and exam
Key diagnostic factors
common
history of exposure
Varicella is normally acquired through contact with a patient with active disease (or, less frequently, direct contact with herpes zoster), so many patients have a history of such exposure. Exposure among children often takes place in the home, school, or daycare environments. Varicella is contagious, with an attack rate of up to 90% in susceptible household members, but attack rates appear to be lower in classroom or daycare environments.[45]
fever
Usually <101.5°F (38°C), but may be as high as 106°F (41°C).[6]
Secondary bacterial infection should be considered in patients with persistent (i.e., >3 days) or recurrent fever.
vesicular rash
Classically described as a dew drop on a rose petal. The rash usually first appears centrally (on the face, scalp, or torso), before spreading to the extremities.[55]
Lesions first appear as macules and quickly develop into fluid-filled vesicles.
As the disease progresses, early lesions will begin to scab over as new peripheral lesions develop. This appearance of lesions in "crops" (i.e., different stages of acuity/healing) is characteristic of varicella.[Figure caption and citation for the preceding image starts]: Typical vesicular rash of primary varicella; note that lesions are in different stagesImage provided by the CDC and the Public Health Image Library [Citation ends].
[Figure caption and citation for the preceding image starts]: Varicella lesions in different stages of healingImage provided by the CDC [Citation ends].
vesicles on mucous membranes
Found most commonly in nasopharynx, but also on other mucous membranes such as conjunctiva, mouth, and vulva. [Figure caption and citation for the preceding image starts]: Varicella lesion on the hard palate of a young patientImage provided by the CDC and the Public Health Image Library [Citation ends].
Other diagnostic factors
common
pruritus
May be a feature in some patients prior to the onset of the rash.
headache
May be a feature in some patients prior to the onset of the rash.
fatigue/malaise
May be a feature in some patients prior to the onset of the rash.
sore throat
May be a feature in some patients prior to the onset of the rash.
tachycardia
May be present in infected patients.
Risk factors
strong
exposure to varicella
Occurs through family contacts or day care- or school-related exposure.
age 1 to 9 years
Most common at-risk group is children ages 1 to 9.
unvaccinated status
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