Chickenpox: Understanding this common childhood illness

 Chickenpox is a highly contagious infectious disease caused by the Varicella-Zoster virus, belonging to the Herpesvirus family. In most cases chickenpox occurs in children between 5 and 10 years, although it may also affect younger or older children, as well as adults.

 Humans are the only reservoirs for the varicella-zoster virus, which is transmitted from child to child through airborne droplets spread by coughing or sneezing or through direct contact with chickenpox skin lesions. Affected children are contagious from 2 days before the rash appears until complete crusting of lesions.

Symptoms, transmission, treatment of Chickenpox

 Symptoms appear after an incubation period of 2 to 3 weeks and include skin rash, low-moderate grade fever, malaise and headache. Skin lesions begin as small itchy, red bumps (called papules) on the face, scalp, trunk and extremities, and then progress to vesicles and finally crusted scabs. In otherwise healthy children the disease is typically mild and recovers by itself within 7 to 10 days without complications. However chickenpox tends to have a more severe course in immunodepressed people, newborn babies, teenagers and adults, who may develop serious complications, including bacterial infection of the skin lesions, pneumonia and occasionally encephalitis (inflammation of the brain).

 Although varicella infection usually confers lifelong immunity and it is unlikely that people develop the disease twice, it has been shown that, once an individual has had chickenpox, the virus remains within the body in a latent (or dormant) form. In some cases the virus can awaken from its latent state after many years or decades from the time of infection, and cause shingles (also called herpes zoster), a condition characterized by a localized painful rash on the skin of the chest.

 Chickenpox treatment is usually symptomatic, based on the use of anti-itch drugs such as antihistamines and anti-fever drugs different from aspirin (because the association between aspirin and chickenpox has been reported to possibly cause a condition called Rye’s syndrome). For people at risk for complications, doctors can prescribe antiviral drugs to shorten the disease course and lower the risk of complications. To avoid the spread of the disease, infected children (as well as other infected people) should stay at home and avoid contact with others for at least 5 days after the rash appears.

Prevention of chickenpox*

 The best way to prevent chickenpox is the varicella vaccine, which is recommended (but not required) for young children, unvaccinated older children or teenagers, as well as non-immunized adults at high risk of exposure, including health care workers, teachers and international travellers. The varicella vaccine should not be administered to immunodepressed patients and pregnant women.