Chickenpox (varicella, ανεμοευλογια)

Από John Hadjiminas Paediatrician

Chickenpox is caused by the Varicella-Zoster virus. The illness begins about 2 weeks [10-21 days] after infection with fever, anorexia, tiredness, headache and abdominal pain. In some children these symptoms are absent. 24-48 hours later the characteristic rash appears. This begins as red spots which then develop a vesicle [bubble with clear fluid content]. Often the rash starts on the head, face and body and then spreads to the legs and arms. The spots appear in groups [crops]. As the first crop starts to develop crusting the next crop appears. There may be as few as 10 spots to as many as 1500 with an average of 300. Lesions appear inside the mouth in the form of ulcers. There is severe itching and children scratch the skin increasing the risk of secondary infection. Scarring is rare in children unless secondary infection occurs.

Although chickenpox is usually a mild disease in some children it can be serious. Newborns are at great risk of developing severe and sometimes fatal disease if the mother develops chickenpox around the time of delivery. The same applies to children who are taking immunosupresant drugs [ treatment of cancer , ulcerative colitis, crohns disease, rheumatoid arthritis etc]. Children with eczema may develop severe disease.

Complications The commonest complication is secondary bacterial infection of the rash, usually due to scratching. Ear infections and pneumonia also occur. Much rarer are the serious complications of encephalitis, hepatitis, haemolytic-uremic syndrome, myocarditis and pancreatitis.

Treatment. This is usually symptomatic with calamine lotion and possibly antihistamine for the itching. Antipyretics for fever and headache plus a light diet and extra fluids are often prescribed. Acyclovir [zovirax] which is an antiviral drug is also available and can shorten the duration and severity of the disease. Antibiotics are given when secondary bacterial infection of the rash, ear infection or pneumonia are present. Serious complications are treated accordingly.

Prevention. A vaccine is available which can be given on its own [Varilrix-GSK] or in combination with Measles-Mumps-Rubella vaccine [Priorix tetra-GSK]. It is given in 2 doses , one at 15 months and one at 4-6 years. In unvaccinated susceptible children who come in contact with the disease administration of vaccine within 3-5 days may stop the disease or make it milder. In immunocompromised children human varicella zoster immune globulin is administered to prevent the disease which can be very serious.