Viruses are small infectious organisms. that are much smaller than a fungus or bacterium. Viruses must invade a living cell to reproduce (see Overview of Viral Infections).
Most childhood viral infections are not serious and include such diverse illnesses as colds, sore throat, vomiting and diarrhea, and fever with a rash. Some viral infections that cause more serious disease, such as measles, are less common now due to widespread immunization. (For adults, see also Overview of Viral Infections.)
Many viral infections are so distinctive that a doctor can diagnose them based on their symptoms. A doctor usually does not need to have a laboratory identify the specific virus involved.
Aspirin is not given to children or adolescents with these symptoms because it increases the risk of Reye syndrome in those who have certain viral infections. Antibiotics cannot cure viral infections. However, there are antiviral drugs available for a few viral infections such as hepatitis, some herpesviruses, influenza, and human immunodeficiency virus (HIV).
Some Viral Infections in Children That Cause a Rash
Infection | Incubation Period* | Contagious Period† | Site of Rash | Nature of Rash in Children |
|---|---|---|---|---|
Measles (rubeola) | 7 to 14 days | From 2 to 4 days before until 4 days after the rash appears | Starts on the face around the ears and on the side of the neck Spreads to the trunk, arms, palms, soles, and legs | Begins a few days after fever and other symptoms and lasts 3 to 5 days Red and flat, then becomes raised and merges into larger red areas Mildly itchy |
Rubella (German measles) | 14 to 21 days | From 1 week before until 1 week after the rash appears (Except in newborns, who usually continue to be contagious for many months) | Starts on the face and neck Spreads to the trunk, arms, and legs | Begins a few days after fever and other symptoms and lasts 3 to 5 days Similar to measles rash but not as red and does not merge to form large red areas |
Roseola infantum (exanthem subitum or pseudorubella) | About 5 to 15 days | Unknown | Starts on the trunk and usually spreads to the face, arms, and legs | Begins within a day after a high fever decreases and lasts for up to 3 days Red and flat, not itchy |
Erythema infectiosum (fifth disease or parvovirus B19 infection) | 4 to 14 days | From before the start of the rash until the rash appears | Starts on the cheeks ("slapped-cheek" appearance) Spreads to the arms, legs, and trunk | Begins a few days after fever and other symptoms and lasts 5 to 10 days Red, raised, blotchy areas with lacy patterns Can be itchy |
Chickenpox (varicella) | 7 to 21 days (most commonly 14 to 16 days) | 2 days before the rash appears until all spots have crusted | Starts on the face and trunk Spreads to the arms and legs | Begins 1 to 2 days after the start of fever and other symptoms and lasts 4 to 7 days Small, red spots that become raised and form very itchy, round, blisters that then crust over |
* The incubation period is the number of days between when a person becomes infected with a virus (or other infections organisms, such as bacteria) and when symptoms begin. | ||||
† The contagious period is the time period that an infected person can spread infection to others. Infections can spread during the contagious period even if people do not have symptoms. | ||||
