Chickenpox (also called varicella) is a common and extremely infectious childhood disease that can also affect adults. It produces an itchy, blistery rashthat typically lasts about a week and is sometimes accompanied by a fever.
Chickenpox has been a typical part of growing up for most children in the industrialized world. About four million Americans contract the disease each year. Chickenpox can strike at any age, but by ages 9 or 10 about 80-90% of American children have already been infected. Because almost every case of chickenpox leads to lifelong protection against further attacks, adults account forless than 5% of all cases in the United States. Adults, however, are much more likely than children to suffer dangerous complications. More than half ofall chickenpox deaths occur among adults.
Chickenpox is caused by the varicella-zoster virus (a member of the herpes virus family), which is spread through the air or by direct contact with an infected person. Once someone has been infected with the virus, an incubation period of about 10-21 days passes before symptoms begin. A case of chickenpox usually starts without warning or with only a mild fever and a slight feelingof unwellness. Soon small red spots begin to appear on the scalp, neck, or upper half of the trunk, and 12 to 24 hours later, the spots become itchy, fluid-filled bumps called vesicles. These blisters continue to appear in crops for the next 2-5 days. Although some people develop only a few blisters, in most cases the number reaches 250-500. Blisters can develop anywhere on the skinand inside the mouth, nose, ears, vagina, or rectum. Occasionally a minor and temporary darkening of the skin (called hyperpigmentation) is noticed around some of the blisters. The blisters soon begin to form scabs and fall off. Scarring usually does not occur unless they have been scratched and become infected. The degree of itchiness can range from barely noticeable to extreme. Some chickenpox sufferers also have headaches, abdominal pain, or a fever.
Treatment usually takes place in the home and focuses on reducing discomfortand fever. Because chickenpox is a viral disease, antibiotics are ineffectiveagainst it.
Applying wet compresses or bathing in cool or lukewarm water once a day can help the itch. Adding four to eight ounces of baking soda or one or two cups of oatmeal to the bath is a good idea. Other recommended remedies to relieve itching include applying calamine lotion, aloe vera, witch hazel, or an herbalpreparations of rosemary (Rosmarinus officinalis) and calendula (Calendual officinalis) to the blisters. Because scratching can cause blisters to become infected and lead to scarring, children with chicken pox shouldhave their nails cut short. For babies, light mittens or socks on the handscan prevent scratching.
If mouth blisters make eating or drinking an unpleasant experience, cold drinks and soft, bland foods can ease discomfort. Painful genital blisters can betreated with an anesthetic cream recommended by a doctor or pharmacist. Antibiotics are often prescribed if blisters become infected.
Fever and discomfort can be reduced by acetaminophen or another medication that does not contain aspirin. Aspirin and any medications that contain aspirin or other salicylates must not be given to children with chickenpox, for they appear to increase the chances of developing Reye's syndrome. The best idea is to consult a doctor or pharmacist if one is unsure about which medications are safe.
Children with chickenpox should be kept home from school during the infectious period of the disease, which is usually about a week. The disease can be spread from one or two days before the rash breaks out until all the blisters have formed scabs, which usually happens 4-7 days later.
Some people are at greater risk for developing complications from chickenpox,the most common of which are bacterial infections of the blisters, pneumonia, dehydration, encephalitis, and hepatitis. Children born to mothers who contract chickenpox just prior to delivery may face an increased possibility of dangerous consequences, including brain damage and death. If the infection occurs during early pregnancy, there is a small (less than 5%) chance of congenital abnormalities. Children less than one year old, and children whose immunesystems have been weakened by a genetic disorder, disease, or medical treatment, may also have complications. Medications which reduce the severity of chicken pox symptoms, including varicella-zoster immune globulin (VZIG) and theantiviral drug acyclovir (Zovirax), or often prescribed to treat immunocompromised children and others at high risk of developing complications.
Medical help should always be sought when anyone in these high-risk groups contracts the disease. In addition, a doctor should be called immediately if anindividual with chicken pox experiences a fever which exceeds102°F (38.9°C) or takes more than four days to disappear. Chicken pox blisters thatare leaking pus or are excessively red, warm, tender, or swollen may be infected and should be examined by a doctor.
If a child with chicken pox seems nervous, confused, or unusually sleepy; complains of a stiff neck or severe headache; shows signs of poor balance or hastrouble walking; finds bright lights hard to look at; is having breathing problems or is coughing a lot; is complaining of chest pain; is vomiting repeatedly; or is having convulsions, get that child to a hospital or medical facility immediately. These may be signs of Reye's syndrome or encephalitis, two rare but potentially very dangerous conditions.
There is one long-term consequence of chickenpox that strikes about 20% of the population, particularly people 50 and older. Like all herpes viruses, thevaricella-zoster virus never leaves the body after an episode of chickenpox,but lies dormant in the nerve cells, where it may be reactivated years laterby disease or age-related weakening of the immune system. The result is shingles (also called herpes zoster), a very painful nerve inflammation, accompanied by a rash, that usually affects the trunk or the face.
A vaccine for chickenpox became available in the United States in 1995 underthe name Varivax. Varivax is a live, attenuated (weakened) virus vaccine. Ithas been found to prevent the disease in 70-90% of the vaccinated population,and in the remaining cases to reduce the severity of an attack. The U.S. Centers for Disease Control (CDC) recommends that the vaccine should be given toall children (with the exception of certain high-risk groups) at 12-18 months of age, preferably when they receive their measles-mumps-rubella vaccine. Vaccination is also recommended for children over 12 who have not had chickenpox.