Pediatric Chickenpox Clinical Presentation

The following are the most common presenting symptoms of varicella:

• Low-grade fever preceding skin manifestations by 1-2 days
• Complaints of abdominal pain by some children
• Pleomorphic rash, usually starting on the head and trunk and spreading to the rest of the body
• Typically, complaints of intense pruritus
• Headache
• Malaise
• Anorexia
• Cough and coryza
• Sore throat

Children with eczema or dermatitis may have severe skin manifestations during varicella.

The history should elicit if a recent outbreak of chickenpox in the community has occurred and if any exposure to varicella at school, daycare, or among family members has occurred. Most patients have a history of exposure in one or more of these three settings. It should also be noted whether the child has previously received varicella vaccine or if the child is immunocompromised (including recent systemic steroid use) to help guide management.

Immunocompromised children often have severe and complicated varicella, and their mortality rate is higher than that in immunocompetent children. Such children are at high risk for developing progressive varicella with multiple organ involvement. These children may have prolonged high fever, prolonged extensive rashes, and hepatitis.

The following categories of patients should be considered immunocompromised:

• Children with any malignancy
• Children on cancer chemotherapy
• Children undergoing high-dose corticosteroid therapy
• Children with congenital cellular immunodeficiencies
• Children on immunosuppressive therapy
• Children with HIV infection

Ask parents whether their child had chickenpox previously. Recently, the validity of reported varicella history as a marker for immunity among unvaccinated individuals has come into question. A recent study recommended that a reported history is no longer highly predictive of seropositivity, suggesting that universal vaccination regardless of history may be prudent.^[16]

Rash and fever are the typical findings during physical examination in pediatric patients with varicella. An ill appearance should raise concern for pulmonary or neurologic complications or serious bacterial superinfection. (See Complications.)

Examination of rash

The diagnosis of varicella is made upon observation of the characteristic chickenpox rash. This rash appears in crops. Skin lesions initially appear on the face and trunk, beginning as red macules and progressing over 12-14 days to become papular, vesicular, pustular, and finally crusted. New lesions continue to erupt for 3-5 days. Lesions usually crust by 6 days (range 2-12 d), and completely heal by 16 days (range 7-34 d). Prolonged eruption of new lesions or delayed crusting and healing can occur with impaired cellular immunity.

An otherwise healthy child usually has 250-500 lesions but may have as few as 10 or as many as 1500. The lesions predominate in central skin areas and proximal upper extremities with relative sparing of distal and lower extremities but spread to other skin areas. Some lesions may appear in the oropharynx. Eye lesions are rare.

Each lesion starts as a red macule and passes through stages of papule, vesicle, pustule, and crust. The vesicle on a lesion’s erythematous base leads to its description as a pearl or dewdrop on a rose petal. Vesicles may occur on mucous membranes and break down to form shallow aphthous ulcers. Vesicles can be hemorrhagic. Redness or swelling around a lesion should lead to suspicion of bacterial superinfection. Dermatomal distribution of lesions is characteristic of reactivation rather than primary infection.

The hallmark of the disease is the simultaneous presence of different stages of the rash.

Assessment of fever

Fever is usually low grade (100-102°F) but may be as high as 106°F. In otherwise healthy children, fever typically subsides within 4 days. Prolonged fever should prompt suspicion of complication or immunodeficiency. Although tachypnea may be seen with fever alone, respiratory distress might represent pneumonitis.

Pneumonia

Perhaps the most serious complication of varicella is viral pneumonia, which primarily occurs in older children and adults. Respiratory symptoms usually appear 3-4 days after the rash. The pneumonia may be unresponsive to antiviral therapy and may lead to death.

Secondary bacterial infections

Varicella may predispose patients to secondary bacterial infections. Signs and symptoms of such infections can be indistinguishable from uncomplicated varicella during the first 3-4 days. Skin lesion infections are common and occur in 5-10% of children. These lesions provide a portal of entry for virulent organisms; rapidly spreading cellulitis, septicemia, and other serious infections may occur. Superficial infection with impetigo is suggestive of potential bacterial superinfection.

The most common infectious organisms are group A streptococci and Staphylococcus aureus. Varicella places the patient at high risk for acquiring invasive group A streptococcal disease.^{[17, 18, 19]} In addition to toxic shock syndrome, group A streptococci may cause necrotizing fasciitis, bacteremia, osteomyelitis, pyomyositis, gangrene, subgaleal abscess, arthritis, and meningitis in patients with varicella.

Staphylococci reportedly cause cellulitis, impetiginous pox infections, staphylococcal scalded skin syndrome, toxic shock syndrome, pericarditis, and osteomyelitis in these patients.

Neurological complications

Acute postinfectious cerebellar ataxia is the most common neurological complication, with an incidence of 1 case per 4000 patients with varicella. Ataxia has sudden onset that usually occurs 2-3 weeks after the onset of varicella. Manifestations may range from mild unsteadiness to complete inability to stand and walk, with accompanying incoordination and dysarthria. Manifestations are maximal at onset; a waxing and waning course suggests another diagnosis. The sensorium is clear, even when the ataxia is profound.

The condition may persist for 2 months. The prognosis for patients with ataxia is good, but a few children may have residual ataxia, incoordination, or dysarthria.

Encephalitis occurs in 1.7 patients per 100,000 cases of varicella among otherwise healthy children aged 1-14 years. The disease manifests during acute varicella a few days after rash onset. Lethargy, drowsiness, and confusion are the usual presenting symptoms. Some children may have seizures, and encephalitis can rapidly progress to deep coma. This serious complication of varicella has a 5-20% mortality rate.

Reye syndrome was associated with varicella when aspirin use was common. Identification of this association now has made acetaminophen the preferred drug, and Reye syndrome has become rare.

Other neurological complications include aseptic meningitis, myelitis (including Guillain-Barré syndrome), polyradiculitis, and meningoencephalitis. A careful neurologic examination can identify associated meningoencephalitis.

Herpes zoster

A delayed complication of varicella, herpes zoster infection, occurs months to years after the primary infection in about 15% of patients. The complication is caused by virus that persists in the sensory ganglions.

Herpes zoster consists of a unilateral vesicular rash, limited to 1-3 dermatomes. The rash is often painful in older children and adults. Among the health benefits of routine varicella immunization in childhood may be a lifelong decreased risk for reactivation of the virus as shingles.

Other complications

About 5% of children with varicella develop otitis media, caused by the usual pathogens.

Hepatitis is a self-limited accompaniment of varicella. Severe hepatitis with clinical manifestations is infrequent in otherwise healthy children with varicella. Liver involvement is independent of the severity of skin and systemic manifestations. Identify right upper quadrant pain with or without associated jaundice.

Retinitis and optic neuritis have been reported as rare complications of varicella in children who are immunocompetent.^[20]

Other reported complications include glomerulonephritis,^[21] hemorrhagic varicella, thrombocytopenia, myocarditis, appendicitis, pancreatitis, Henoch-Schönlein purpura, orchitis, iritis, and keratitis. Extracutaneous complications increase proportionately to the age of the patient.

Outcomes of in utero varicella infections vary based on the timing of the infection.

Congenital varicella syndrome

Congenital varicella syndrome occurs in 2% of children born to women who develop varicella during the first or second trimester of pregnancy.^[22] It manifests as intrauterine growth retardation, microcephaly, cortical atrophy, limb hypoplasia, microphthalmia, cataracts, chorioretinitis, and cutaneous scarring. Fetal injury risk is unrelated to the severity of disease in the mother. Zoster exposure during pregnancy has not been associated with fetal injury.

Infantile zoster

Infantile zoster is caused by maternal varicella infection after 20 weeks’ gestation. It usually manifests within the first year of life and commonly involves the thoracic dermatomes.^[23]

Neonatal varicella

Neonatal varicella can be a serious illness, depending on the timing of maternal varicella and delivery. After the initial viremia, the mother develops antibodies against the varicella virus. The severity of the disease in the newborn depends on whether transplacental passage includes only the virus or includes both the virus and the antibodies.

If the mother develops varicella within 5 days before or 2 days after delivery, the baby is exposed to the secondary viremia of the mother. The baby transplacentally acquires the virus but acquires no protective antibodies because of insufficient time for antibodies to develop in the mother. In these babies, neonatal varicella is likely to be severe and disseminated. Hemorrhagic lesions of the liver and lungs characterize this potentially fatal disease.

Onset of maternal varicella more than 5 days ante partum provides the mother sufficient time to manufacture and pass on antibodies along with the virus. Full-term neonates of these women usually have mild varicella because of the attenuating effect of the transplacentally acquired antibodies.