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For further information, see CMDT Part 32-01: Human Herpesviruses
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Essentials of Diagnosis
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Varicella rash: pruritic, centrifugal, papular, changing to vesicular ("dewdrops on a rose petal"), pustular, and finally crusting
Zoster rash: tingling, pain, eruption of vesicles in a dermatomal distribution, evolving to pustules and then crusting
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General Considerations
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Varicella (chickenpox)
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Fever and malaise mild in children, marked in adults
Vesicular eruptions often first involve oropharynx
Rash involves face, scalp, and trunk and then moves out to the extremities
Lesions erupt over 1–5 days so all stages of eruption present simultaneously
Vesicles and pustules are superficial, elliptical, with slightly serrated borders
Multinucleated giant cells on Tzanck smear of materials from vesicle bases
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Herpes zoster (shingles)
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Pain is often severe and precedes the lesions
Lesions follow any nerve route distribution (thoracic and lumbar most common)
Vesicular skin lesions resemble varicella
Lesions on tip of nose, inner corner of eye, and root and side of nose (Hutchinson sign) indicate potential ophthalmic involvement
Facial palsy, vertigo, tinnitus, deafness, or external ear lesions suggest geniculate ganglion involvement
Associations between recent attacks of zoster and the development of multiple sclerosis and Guillain Barré syndrome are recognized
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Differential Diagnosis
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Varicella (chickenpox)
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Herpes simplex (cold or fever sore; genital herpes)
Herpes zoster (shingles)
Contact dermatitis
Scabies
Atopic dermatitis (eczema) (acute)
Miliaria (heat rash)
Photodermatitis
Smallpox
Rickettsialpox
Hand, foot, and mouth disease
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Herpes zoster (shingles)
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Contact dermatitis (eg, poison oak or ivy)
Herpes simplex
Varicella (chickenpox)
Erysipelas
Prodromal pain mimics angina, peptic ulcer, appendicitis, biliary or renal colic
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Leukopenia often present in varicella
Zoster symptoms and signs often highly characteristic, not requiring further diagnostic testing
When diagnosis remains in doubt, direct fluorescent antibody (DFA) testing, viral culture, and polymerase chain reaction (PCR) testing can be helpful
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VariZIG reduces the severity of varicella in high-risk children or adults (eg, those with impaired immunity, pregnant women, and infants exposed peripartum) if given within 4 days of exposure
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