A virus is a small infectious organism—much smaller than a fungus or bacterium—that must invade a living cell to reproduce (see Overview of Viral Infections).
Viral infections are common among people of all ages but often seem to be concentrated in infants and children. 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 illnesses that cause more serious disease, such as measles, are less common now due to widespread immunization. Several types of viral infections that children can acquire are discussed in adult viral infections.
Generally, parents can tell whether their child is ill with a potentially serious infection and needs immediate medical care. This is particularly true for children beyond infancy. 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.
Most children with viral infections get better without treatment. Many viral infections result in fever and body aches or discomfort. Doctors sometimes treat these symptoms with acetaminophen or ibuprofen. 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 |
Period of Incubation |
Period of Contagiousness |
Site of Rash |
Nature of Rash |
|
Measles (rubeola) |
7 to 14 days |
From 2 to 4 days before the rash appears until 2 to 5 days after |
Starts around the ears and on the face and neck Spreads to the trunk, arms, and legs |
Begins 3 to 5 days after the start of fever, runny nose, cough, red eyes, and sore throat and lasts 3 to 5 days Irregular, flat, red areas that soon become raised |
|
Rubella (German measles) |
14 to 21 days |
From a week before the rash appears until a week after it appears Infected newborns are usually contagious for many months |
Starts on the face and neck Spreads to the trunk, arms, and legs |
Begins 1 or 2 days after the start of mild fever, swollen and tender lymph nodes, red eyes, and headache and lasts 3 to 5 days Fine, pinkish, flat rash |
|
Roseola infantum (exanthem subitum or pseudorubella) |
About 5 to 15 days |
Unknown |
Starts on the trunk and usually spreads to the neck, face, arms, and legs |
Begins on about the 4th day after the start of a high fever and usually just when the fever ends and lasts for hours to a few days Pinkish red, flat or raised rash |
|
Erythema infectiosum (fifth disease or parvovirus B19 infection) |
4 to 14 days |
From before the start of the rash until 1 to 2 days after |
Starts on the cheeks Spreads to the arms, legs, and trunk |
Begins several days after the start of low fever, headache, and runny nose and lasts 5 to 10 days May recur for several weeks Red rash on the cheeks (slapped-cheek rash) spreads to the arms, legs, and trunk and becomes lighter and blotchy with lacy patterns |
|
Chickenpox (varicella) |
11 to 15 days |
From a few days before the start of symptoms until all spots have crusted |
Starts on the face, neck, and trunk Spreads to the arms, legs, and scalp |
Appears in crops, so various stages are present simultaneously Begins shortly after the start of fever and feeling of illness and lasts a few days to 2 weeks Small, flat, red spots that become raised and form round, fluid-filled blisters against a red background before finally crusting |
