Chicken pox

What is chicken pox ?

• It is an infectious condition caused by a virus called Varicella Zoster Virus (VZV).
• It typically affects children.

Does it always present ?

• Once infected, lesions present only after two to three weeks (incubation period).
• In 30% of cases, there is no obvious manifestation (subclinical).

How does it look like ?

• At first redness appears on the trunk, scalp and mouth (oral mucosa).
• Then lesions become blisters and then pustules.
• At the end they “dry out” (crusting), leaving scabs.
• The main thing to remember is that there is no typical individual feature; the easiest is to detect a mixed group of lesions at different stages of development.
• There is intense itching. The scratching of lesions leads to infection and subsequent scarring.
• The palms and soles are spared.

Is it contagious ?

• Chicken pox is extremely contagious and isolation is a requirement.
• The condition remains contagious until all the lesions have “dried out”.

How is it treated ?

• Symptomatic treatment is most often enough and consists of drying lotions (astringents) , disinfectants, topical and systemic antibiotics, antihistaminics.
• Acyclovir slightly reduces the course of the disease.
• Isolation is the single most important attitude.
• If isolation is not possible, inpatient treatment may be required.
• Also intravenous treatment with anti-VZV immunoglobulins is necessary if  there is pulmonary (herpetic pneumonitis) or cerebral (herpetic encephalitis) involvement.

Is it preventable ?

• Yes. Varicella vaccine is a routine childhood immunization.

Chicken pox during pregnancy: what are the risks ?

• There are risks for the baby at all trimesters (I and II: varicella embryopathy syndrome, III: congenital varicella).
• It is important in those cases to be closely followed by a paeditrician and gynaecologist.

What are the long term consequences ?

• The VZV virus remains in the dorsal nerve ganglia and can be reactivated many years later.
• In that case it produces a localized (dermatomal) eruption of blisters and is preceeded by tingling / pain. This condition is called shingles:

1. the biggest problem is the presence of an “electrical” pain after the eruption subsides (post herpetic neuralgia). This problem  occurs quite often in individuals aged 60 and over.
2. a vaccine is available against shingles.

Biblography: Sterry W. et al. Thieme Clinical Companions: Dermatology. 1st edition in English.