• The incubation period of varicella is 10-21 days. A prodromal period of 1-3 days, characterized by fever and respiratory symptoms, precedes the onset of symptoms, particularly in older children.
• While primary infection of varicella provides lifelong immunity, the virus remains in the sensory ganglia in 10-15% of cases and reappears as herpes zoster in adulthood.
• In herpes zoster, pain that can last for days is seen before the rash.
• In primary infection of varicella, spread is by droplet and approximately 95% of susceptible children will definitely have an infection. Herpes zoster is contagious at a rate of 30%.
Clinic
varicella
• Varicella rash; macule-vesicle-pustule-crust respectively. After these crusts fall off, the lesions heal without scarring.
• The rash is mainly seen on the face and trunk. Less commonly, it can be seen on the scalp, nose, mouth and intestines.
• In varicella, old and new lesions can be seen at the same time, while in smallpox, all the lesions are at the same stage.
• Usually the lesions are extremely itchy. Infectiousness disappears after all the lesions have crusted over.
Herpes Zoster
• Rashes are usually seen in the truncal or cranial region and along a single dermatome and do not cross the midline.
• A few vesicles may be seen, except for the area of the involved dermatome. The crusting time of the lesions is 7-10 days. Shingles zoster is common in HIV-infected children.
• Corneal involvement can be seen in ophthalmic zoster. Postherpetic neuralgia is rare in children.
• It is the most common infection in Hodgkin's disease.
Complications
1. Secondary bacterial infections (most common complication): Impetigo, cellulitis, lymphadenitis, subcutaneous abscess
2. Cerebellitis (the most common CNS complication): It progresses with ataxia, its prognosis is good.
3. Reye's syndrome (associated with the use of salicylates): Salicylate is not recommended for those who have had chickenpox.
4. Pneumonia: Varicella pneumonia classically causes multiple bilateral nodular densities and hyperaeration. It is common in immunodeficiency, pregnant women and the elderly.
5. Rare complications:
• Hepatitis
• Thrombocytopenia and hemorrhages
• Nephritis and nephrotic syndrome
• Hemolytic uremic syndrome
• Myocarditis
• Arthritis
• Pancreatitis and orchitis
• Acute retinal necrosis
Diagnosis-Treatment
• Diagnosis is made with clinical findings. Multinuclear giant cells are seen in the cytological staining (Tzanck test) of the swab taken from the base of the vesicle, suggesting varicella zoster or HSV infection.
• No specific treatment is recommended for healthy children. Acyclovir treatment is recommended in immunocompromised patients and foscarnet (pyrophosphate analogue) treatment in resistant cases. In the case of foscarnet resistance, cidofovir is used.
Acyclovir indications
• Those with weakened immune systems (transplant recipients, HIV)
• Pneumonia, hepatitis, encephalitis, thrombocytopenia
• > 12 years
• Those with chronic lung problems (cystic fibrosis)
• Those with chronic skin disease (atopic dermatitis, chronic seborrheic dermatitis)
• Those receiving aspirin therapy
• Neonatal varicella
• Cases developing secondary to domestic contact
• Those receiving steroid therapy (including inhalers)
Protection
• There is a live vaccine available from 12 months of age.
Protection in case of suspicious contact
• Vaccination within 3-5 days after suspected contact
• Passive protection is provided if varicella zoster immunoglobulin (VZIG) is administered within 96 hours or standard immunoglobulin is administered within 96 hours.
• VZIG is the first choice for post-exposure protection under 1 year of age and immunodeficiency.
Neonatal varicella prophylaxis
• Babies whose mothers have chickenpox between 5 days before birth and 2 days after birth are born normally, but soon develop severely disseminated varicella. Therefore, these babies should be given VZIG as soon as they are born.
• Since perinatally transmitted varicella can be life-threatening, acyclovir should be given to babies with lesions.
• Acyclovir should be given to FDs (especially severe and complicated cases) diagnosed with community-acquired varicella.
• If hospitalized premature babies <28 weeks or <1000 g come into contact with varicella, VZIG should be given regardless of the mother's immunization status.
• ≥ 28 weeks - VZIG should be given if there is contact with varicella and the mother is not immunized.
• VZIG should be given to high-risk patients in close contact with herpes zoster.