Chickenpox

Symptoms of chickenpox begin 7 to 21 days after infection occurs. They include

Younger children often do not have these symptoms, but symptoms are often severe in adults.

About 24 to 36 hours after the first symptoms begin, a rash of small, flat, red spots appears. The spots usually begin on the trunk and face, later appearing on the arms and legs. Some people have only a few spots. Others have them almost everywhere, including on the scalp and inside the mouth.

Within 6 to 8 hours, each spot becomes raised. It forms an itchy, round, fluid-filled blister against a red background and finally crusts. Spots continue to develop and crust for several days. A hallmark of chickenpox is that the rash develops in crops so that the spots are in various forms of development at any affected area. Very rarely, the spots become infected by bacteria, which can cause a severe skin infection (cellulitis Cellulitis Cellulitis is a spreading bacterial infection of the skin and the tissues immediately beneath the skin. This infection is most often caused by streptococci or staphylococci. Redness, pain, and... read more or necrotizing fasciitis Necrotizing Skin Infections Necrotizing skin infections, including necrotizing cellulitis and necrotizing fasciitis, are severe forms of cellulitis. These infections cause infected skin and tissues to die (necrosis). The... read more ).

New spots usually stop appearing by the fifth day, the majority are crusted by the sixth day, and most disappear in fewer than 20 days.

Sometimes children who have been vaccinated develop chickenpox. In these children, the rash is typically milder, fever is less common, and the illness is shorter. However, contact with the sores can spread the infection.

Spots in the mouth quickly rupture and form raw sores (ulcers), which often make swallowing painful. Raw sores may also occur on the eyelids and in the upper airways, rectum, and vagina. The worst part of the illness usually lasts 4 to 7 days.

A doctor is usually certain of the diagnosis of chickenpox because the rash and the other symptoms are so typical.

Blood tests to measure levels of antibodies in the blood and laboratory tests to identify the virus (usually using a sample scraped from the sores) are rarely needed. (Antibodies Antibodies One of the body's lines of defense ( immune system) involves white blood cells (leukocytes) that travel through the bloodstream and into tissues, searching for and attacking microorganisms and... read more are produced by the immune system to help defend the body against a particular attacker, such as the varicella-zoster virus.)

Healthy children nearly always recover from chickenpox without problems. Before routine immunization, about 4 million people developed chickenpox annually in the United States, and about 100 to 150 of them died each year because of complications of chickenpox.

In adults, chickenpox is more severe, and the risk of dying is higher.

Chickenpox is particularly severe in people with a weakened immune system Overview of Immunodeficiency Disorders Immunodeficiency disorders involve malfunction of the immune system, resulting in infections that develop and recur more frequently, are more severe, and last longer than usual. Immunodeficiency... read more .

When people who have been vaccinated Varicella Vaccine The varicella vaccine helps protect against chickenpox (varicella), a very contagious infection caused by the varicella-zoster virus. It causes an itchy rash that looks like small blisters with... read more develop chickenpox, the disease is less severe, and fewer of these people die.

Mild cases of chickenpox in children require only the treatment of symptoms. Wet compresses on the skin help soothe itching, which may be intense, and prevent scratching, which may spread the infection and cause scars. Because of the risk of bacterial infection, the skin is bathed often with soap and water, the hands are kept clean, the nails are clipped to minimize scratching, and clothing is kept clean and dry. If the itching is severe, drugs that relieve itching, such as antihistamines, may be given by mouth. Taking colloidal oatmeal baths may also help.

If a bacterial infection develops, antibiotics may be needed.

Doctors usually prescribe antiviral drugs Antiviral drugs A virus is composed of nucleic acid, either DNA or RNA, surrounded by a protein coat. It requires a living cell in which to multiply. A viral infection can lead to a spectrum of symptoms from... read more , such as acyclovir, valacyclovir, and famciclovir (see table Some Antiviral Drugs for Herpesvirus Infections Some Antiviral Drugs for Herpesvirus Infections ), by mouth to certain healthy people at risk of moderate to severe disease, including people

For people over 1 year of age who have a weakened immune system, doctors may prescribe acyclovir given by vein (IV).

Antiviral drugs can reduce the severity and duration of symptoms and should be given within 24 hours of the start of disease, if possible.

Because pregnant women are at high risk of severe complications from chickenpox, some experts recommend treating pregnant women who have chickenpox with acyclovir or valacyclovir.