Chickenpox (varicella)

Posted on: Thursday, June 14th, 2018 @ 7:41 PM - By: Mohemet - Seen 1286 Times

Chickenpox (varicella) is a common and highly contagious viral illness caused by varicella-zoster virus (VZV). Although chickenpox can occur at any age even in neonates, most cases are usually seen between the ages of 2-10 years.

Persons with varicella are contagious 1-2 days before the rash and until all vesicles are crusted, usually 3~7 days after onset of rash. VZV is transmitted by contact with oropharyngeal secretions and the fluid of skin lesions of infected individuals, either by airborne spread or through direct contact. Isolation is recommended for 1 week and child can return to school after 7-10 days.

Signs and symptoms

Prodromal symptoms begin 24-48 hr before the rash as fever, malaise, anorexia, headache, and occasionally mild abdominal pain; these symptoms usually resolve within 2-4 days after the rash.

Varicella lesions often appear first on the scalp, face, or trunk. Initial exanthem consists of intensely pruritic erythematous macules that evolve through the papular stage to form clear, fluid-filled vesicles. While the initial lesions are crusting, new crops form on the trunk and then the extremities; the simultaneous presence of lesions in various stages of evolution is characteristic of varicella (polymorphic rash). The distribution of the rash is predominantly central or centripetal with the greatest concentration on the trunk and proximally on the extremities. Ulcerative lesions involving the mucosa of the oropharynx and vagina are also common.

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Diagnosis

Diagnosis of varicella is mainly clinical, however serology: 4-fold or greater rise in VZV lgM antibodies is confirmatory of acute infection.

Mangement

Management of chickenpox includes the following aspects:

1. Measures to control itching e.g.

-Antihistamines: allermine syrup or (fenistil drop in very young infants) are helpful in reducing itching.

-Local application of soothing agents: Calamine lotion twice or thrice daily may be also useful.

Calamine should be applied by a piece of cotton to rashes only not to the whole body, and should not be applied to face at all even to the rashes!

-Fingernails should be kept cut: This is important to prevent scratching and to avoid secondary bacterial infection.

2. Controlling fever and pain e.g. by Paracetol syrup or suppository (15mg/kg/dose 4 times daily).

3. Antiviaral treatment for complicated or disseminated varicella e.g. acyclovir, to be most effective, treatment of Varicella should be initiated as early as possible. Oral therapy with acyclovir syrup (20 mg/kg/dose; maximum: 800 mg/dose] given as 4 doses/day for 5 days.

Note: Acyclovir therapy is not recommended routinely by the AAP for Rx of uncomplicated varicella in otherwise healthy child.

4. Antibiotics: They are only indicated in secondary bacterial infection. Oral erythromycin (50 mg/kg/day, in 3 divided doses) or a first-generation cephalosporin as cephalexin (50 mg/kg/day, in 3 divided doses) can be used for 5-7 days.

Exposed siblings between the  ages of 1-10 years need no protective measures, but neonates and young infants should receive passive immunization by IM gammaglobulin injection (1 ~ 2 ml, IM). Patients with immunodeficiency or those receiving immunosuppressive drugs should also receive prophylaxis.

Filed under: Infectious diseases