Chickenpox is a viral disease characterized by itching and a skin rash with fluid-filled blisters that burst and form crusts. The onset of the chickenpox rash may be preceded by fever and general malaise.

The rash begins with a few small, reddish bumps (papules) that quickly fill with fluid to form small blisters (vesicles). The vesicles appear in "crops," small groupings, first on the trunk then spreading to the extremities, face, and scalp over a period of two to four days.

The rash may spread into the mouth and other internal parts of the body. The vesicles break, and a light brown scab or crust forms over the top. This crust gradually darkens to a dark brown before it finally falls off, usually within two weeks of the onset of the illness.

Chickenpox itself seldom causes scarring. However, chickenpox lesions can become infected, often due to vigorous scratching. Some of these secondary infections may be severe enough to require hospitalization.

Chickenpox is spread from person-to-person by contact with infected respiratory droplets, or by contact with articles freshly soiled by discharge from the lesions. It is contagious from two days before the onset of the rash, until all of the lesions are crusted over.

The incubation period is 10 to 21 days. There is universal susceptibility to the virus in those not vaccinated or previously infected. After infection, lifelong immunity against recurrent infection is usually present. However, a person with a history of chickenpox may develop shingles (herpes zoster) later in life.

• achy and feverish
• a skin rash or lesion on the chest, back, shoulders, scalp, or other areas
• lesions on the mouth, vagina, rectum, eye, or other mucous membranes
• the rash changes to fluid-filled blisters
• crusting, after the blister breaks
• crusts become progressively darker with time
• scabs fall off in about 9 to 13 days
• itching -- may be severe

General measures to relieve itching associated with skin lesions include cool water soaks or compresses. Some over-the-counter creams may be helpful. Fingernails should be trimmed to prevent scratching, which may lead to a secondary infection.

Infant's hands may be covered with a soft cotton or flannel mitten to prevent scratching (the hand should never be restrained).

DO NOT USE ASPIRIN! To reduce fever and relieve pain, use acetaminophen instead. Aspirin use during a viral illness, particularly chickenpox, has been associated with a risk of developing Reye's syndrome.

The prescription drug Acyclovir may be recommended by your doctor, but is generally used only in children with altered immune systems or those at high risk for serious complications.

Children should be kept home from school or day-care until all of the blisters have broken and scabbed over, and they feel well enough to participate in normal activities.

• Women who acquire chickenpox during pregnancy are at risk for congenital infection of the fetus.
• Newborns are at risk for severe infection, if they are exposed and their mothers are not immune.
• Secondary infection of blisters (vesicles) may occur.
• Encephalitis is a serious, but rare complication.
• Reye's syndrome, pneumonia, myocarditis, and transient arthritis are other possible complications of chickenpox
• Cerebellar ataxia may appear during the convalescent phase or later. This is characterized by a very unsteady walk.

Varicella vaccine is recommended as a routine immunization for children 12 months and older. In some children at high risk for complications of chickenpox, varicella vaccine or varicella zoster immune globulin (VZIG) may prevent or improve the recovery from the disease if given shortly after exposure -- talk to your doctor if your child has been exposed.