Chickenpox (also called varicella) is a highly contagious viral disease that affects skin and mucous membranes. Most cases occur in young people, often children 2 to 8 years old. Adults usually have a more severe illness that lasts longer.
People develop immunity or resistance to chickenpox when they get it the first time and are unlikely to get it again. Some people may later develop shingles (herpes zoster), a reactivation of chickenpox virus, if their immunity weekens.
Immunizations with varicella-zoster vaccine can prevent chickenpox and shingles.
The cause is varicella-zoster herpesvirus. People catch chickenpox, when they are around someone who has it, by breathing in droplets containing virus. People also catch it by direct contact with skin lesions on infected people.
Symptoms develop 7 to 21 days after exposure. They include slight fever, runny nose, slight cough, headache, tiredness, and no appetite.
Red spots that appear on the body 2 to 3 days later develop into an itchy rash that forms blisters, which dry and become scabs in 4 to 5 days. People may have only a few blisters, or more than 500 may appear. Chickenpox is usually contagious 1 to 2 days before the rash and up to 6 days after blisters form. The mouth, ears, and eyes can also have ulcers.
The health care provider will make a diagnosis by the medical history and by looking at the rash.
Healthy children need no specific medicine but can get symptom relief. Nonaspirin products such as acetaminophen can reduce fever. DON’T give aspirin to children with chickenpox. Antihistamines, lotions such as calamine, and oatmeal baths can reduce itching. Drinking liquids and resting are recommended. To prevent spreading chickenpox, keep children away from others until blisters have crusted.
People at high risk for severe infection and people with impaired immune systems (e.g., those with bone marrow transplants or leukemia) may get antiviral drugs to prevent complications from chickenpox.
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