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 Overview of Viral Infections 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 ).
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 Sore Throat Sore throat is pain in the back of the throat. The pain can be severe and is usually worsened by swallowing. Many people with sore throat refuse to eat or drink. Sometimes pain is also felt... read more 
, vomiting Vomiting in Infants and Children Vomiting is the uncomfortable, involuntary, forceful throwing up of food. In infants, vomiting must be distinguished from spitting up. Infants often spit up small amounts while being fed or... read more and diarrhea Diarrhea in Children Diarrhea is a very common problem in children (see also Diarrhea in adults). Diarrhea is frequent, loose, or watery bowel movements (BMs) that differ from a child’s normal pattern. Sometimes... read more , and fever Fever in Infants and Children Normal body temperature varies from person to person and throughout the day (it is typically highest in the afternoon). Normal body temperature is higher in preschool-aged children and highest... read more 
with a rash Rashes in Children A rash is an abnormal change in the texture or color of the skin. Known causes of rashes include irritation and bacterial, fungal, or viral infections. Symptoms include redness, white or yellow... read more 
. Some viral illnesses that cause more serious disease, such as measles Measles Measles is a highly contagious viral infection that causes various cold-like symptoms and a characteristic rash. Measles is caused by a virus. Symptoms include fever, runny nose, hacking cough... read more 
, are less common now due to widespread immunization. Several types of viral infections that children can acquire are discussed in adult viral infections Overview of Viral Infections 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 .
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 Reye Syndrome Reye syndrome is a very rare but life-threatening disorder that causes inflammation and swelling of the brain and impairment and loss of function of the liver. The cause of Reye syndrome is... read more in those who have certain viral infections. Antibiotics cannot cure viral infections. However, there are 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 available for a few viral infections such as hepatitis Overview of Hepatitis Hepatitis is inflammation of the liver. (See also Overview of Acute Viral Hepatitis and Overview of Chronic Hepatitis.) Hepatitis is common throughout the world. Hepatitis can be Acute (short-lived) read more , some herpesviruses Overview of Herpesvirus Infections Some common viral infections are caused by herpesviruses. Eight different herpesviruses infect people: Three herpesviruses—herpes simplex virus type 1, herpes simplex virus type 2, and varicella-zoster... read more , influenza Influenza (Flu) Influenza (flu) is a viral infection of the lungs and airways with one of the influenza viruses. It causes a fever, runny nose, sore throat, cough, headache, muscle aches (myalgias), and a general... read more , and human immunodeficiency virus (HIV) Human Immunodeficiency Virus (HIV) Infection in Children Human immunodeficiency virus (HIV) infection is a viral infection that progressively destroys certain white blood cells and causes acquired immunodeficiency syndrome (AIDS). Human immunodeficiency... read more .
Some Viral Infections in Children That Cause a Rash
Infection | Period of Incubation | Period of Contagiousness | Site of Rash | Nature of Rash |
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 | |
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 | |
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 | |
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 | |
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 |
