Varicella Diagnosis

Varicella (Chickenpox)

• Isolation of VZV on cell cultures is not used anymore.
• Tzanck test is used for diagnosis.

Differential Diagnosis

• Scarlet fever
• Measles
• Rubella

Scarlet Fever

• Rash is maculopapular, "sandpaper"-like, and not itchy.
• Respects palms and soles.
• Fades on the 24-48h after palms and soles.
• Filatov Mask and Grozovici-Pastia sign may be present.

Measles

• Rash develops on the face on Day 1, trunk on Day 2, and extremities on Day 3.
• Rash is maculopapular, not itchy, and becomes brownish after a few days.
• Conjunctivitis is present.
• Koplik sign may be present.

Rubella

• Rash is very discrete, pink-colored, and begins on the face but only lasts for a day.
• Forscheimer dots may be present.
• Lymphadenopathies persist for weeks.

Complications of Varicella

• Pneumonia, often seen in adults, pregnant patients, ID patients, and newborns.
• Bacterial superinfection, neurologic complications (meningitis, encephalitis, etc.), and other organs can be affected.
• Reye syndrome, an acute encephalopathy associated with hepatic dysfunction, can occur if aspirin is administered.

Treatment of Varicella

• Antiviral treatment is recommended for patients aged >12 years, severe cases, ID patients, newborns, pregnant patients, and those with chronic treatment with aspirin/corticosteroids or atopic dermatitis.
• Acyclovir is the antiviral drug of choice, with doses depending on the severity of the case.
• Valacyclovir is an alternative treatment.
• Immunocompetent children with mild varicella can be treated with symptomatic treatment only.

Prophylaxis

• Passive immunization with specific anti-VZV immunoglobulins (anti-VZV IgG) can be used in pregnant patients, newborns, and those who come into contact with a confirmed case.
• Must be administered within 72-96h after contact.

Epidemiology of Varicella

• Incubation period is 10-21 days.
• Prodrome lasts 1-2 days.
• Eruption lasts 10-15 days.
• Asymptomatic cases can occur.

Clinical Presentation of Varicella

• Rash is polymorphic, very itchy, and develops in crops.
• Each element goes through the following stages: macule, papule, vesicle, umbilicated vesicle, and crust.
• The elements don't scar unless they become superinfected.

This quiz covers the diagnosis and differentiation of varicella (chickenpox) from other diseases such as scarlet fever, measles, and rubella. It includes the Tzanck test and characteristic rash symptoms.