RELATED STORIES • Chickenpox • Croup • Measles study stresses importance of routine vaccination • Hand-foot-and-mouth disease • Chickenpox vaccine: Is it always effective? • Coxsackievirus infection INFECTIOUS DISEASE Viral Illnesses • Chickenpox • Mumps • Postherpetic neuralgia • Croup • Measles • Rubella • Mononucleosis • Smallpox • Parvovirus infection • West Nile virus • Roseola • Rabies • SARS • Viral hemorrhagic fevers • Polio • Hand-foot-and-mouth disease

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Roseola is a generally mild infection that usually affects children between 6 months and 3 years of age, though it occasionally affects adults. It's extremely common — so common, in fact, that most children have been infected by roseola by the time they enter kindergarten.

Two common strains of the herpes virus cause roseola. The condition typically causes several days of fever, followed by a rash.

Some children develop only a very mild case of roseola and never show any clear indication of illness, while others experience the full range of signs and symptoms. The infection can occur at any time of the year.

Roseola typically isn't serious. Rarely, complications from a very high fever can result. Treatment of roseola includes bed rest, fluids and medications to reduce fever.

If your child is exposed to someone with roseola and becomes infected with the virus, it generally takes a week or two for signs and symptoms of infection to appear — if they appear at all. It's possible to become infected with roseola but have signs and symptoms too mild to be readily noticeable. Signs and symptoms may include:

• Fever. Roseola typically starts with a sudden, high fever — often greater than 103 F. Some children may also have a slightly sore throat or a runny nose along with or preceding the fever. Your child may also develop swollen glands in his or her neck along with the fever. The fever lasts for three to seven days.
• Rash. Once the fever subsides, a rash typically appears — but not always. The rash consists of many small pink spots or patches. These spots are generally flat, but some may be raised. There may be a white ring around some of the spots. The rash usually starts on the chest, back and abdomen and then spreads to the neck and arms. It may or may not reach the legs and face. The rash, which isn't itchy or uncomfortable, can last from several hours to several days before fading.

Other signs and symptoms of roseola may include:

• Fatigue
• Irritability in infants and children
• Mild diarrhea
• Decreased appetite
• Swollen eyelids

The most common cause of roseola is the human herpes virus 6 (HHV6), but the cause also can be another herpes virus — human herpes virus 7 (HHV7). These herpes viruses are related to, but different from, those that cause cold sores and genital herpes.

Like other viral illnesses, such as a common cold, roseola spreads from person to person through contact with an infected person's respiratory secretions or saliva. For example, a healthy child who shares a cup with a child who has roseola could contract the virus.

Roseola is contagious even if no rash is present. That means the condition can spread while an infected child has only a fever, even before it's clear that the child has roseola. Watch for signs of roseola if your child has interacted with another child who has the illness. Unlike chickenpox and other childhood viral illnesses that spread rapidly, roseola rarely results in a communitywide outbreak.

Older infants are at greatest risk of acquiring roseola because they haven't had time yet to develop their own antibodies against many viruses. While in the uterus, babies receive antibodies from their mothers that protect them as newborns from contracting infections, such as roseola. But that immunity fades with time. The most common age for a child to contract roseola is between 6 and 12 months.

Roseola can cause a high fever — 103 F or higher. Call your child's doctor anytime your child has a fever greater than 103 F. The doctor may want to examine your child to rule out more serious causes of fever.

Your child could have a convulsion (febrile seizure) if his or her fever becomes too high or spikes too quickly. However, usually by the time you notice your child's high temperature, the threat of a possible seizure has already passed. If your child does have an unexplained seizure, seek medical care immediately.

If your child has roseola and the fever lasts more than seven days, or if the rash doesn't improve after three days, call your child's doctor.

If your immune system is compromised and you come in contact with someone who had roseola, contact your doctor. You may need monitoring for a possible infection that, for you, could be more severe than it is for a child.

Roseola can be difficult to diagnose because initial signs and symptoms are similar to those of other common childhood illnesses, such as the common cold or an ear infection. If it's clear that no cold, ear infection, strep throat or other common condition is present, your doctor may wait to see if the characteristic rash of roseola appears. Your doctor may tell you to look for the rash while you treat your child's fever at home.

Doctors confirm a diagnosis of roseola by the telltale rash or, in some cases, by a blood test to check for antibodies to roseola.

Occasionally a child with roseola experiences a seizure brought on by a rapid rise in body temperature. If this happens, your child might briefly lose consciousness and jerk his or her arms, legs or head for several seconds to minutes. He or she may also lose bladder or bowel control temporarily.

If your child has a seizure, seek emergency care. Although frightening, fever-related seizures in otherwise healthy young children are generally short-lived and are rarely harmful.

Complications from roseola are rare. The vast majority of otherwise healthy children and adults with roseola recover quickly and completely.

Concerns for people with weak immune systems
Roseola is of greater concern in people whose immune system is compromised, such as those who have recently received a bone marrow or organ transplant. They may contract a new case of roseola — or a previous infection may come back while their immune system is weakened. Because they have less resistance to viruses in general, immune-compromised people tend to develop more severe cases of infection and have a harder time fighting off illness.

People with weak immune systems who contract roseola may experience potentially serious complications from the infection, such as pneumonia or encephalitis — a potentially life-threatening inflammation of the brain.

Most children recover fully from roseola within a week of the onset of the fever. With your doctor's advice, you can give your child over-the-counter medications to reduce fever, such as acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin, others). However, don't give aspirin to a child who has a viral illness because aspirin has been associated with the development of Reye's syndrome, which can be serious.

There's no specific treatment for roseola, although some doctors may prescribe the antiviral medication ganciclovir (Cytovene) to treat the infection in people with weakened immunity. Antibiotics aren't effective in treating viral illnesses, such as roseola.

Because there's no vaccine to prevent roseola, the best you can do to prevent the spread of roseola is to avoid exposing your child to an infected child. If your child is sick with roseola, keep him or her home and away from other children until the fever has broken. Once the rash appears, the virus is much less contagious.

Most people have antibodies to roseola by the time they're of school age, making them immune to a second infection. Even so, if one household member contracts the virus, make sure that all family members wash their hands frequently to prevent spread of the virus to anyone who isn't immune.

Adults who never contracted roseola as children can become infected later in life, though the disease tends to be mild in healthy adults. The main concern is that infected adults can pass the virus on to children.

Like most viruses, roseola just needs to run its course. Once the fever subsides, your child should feel better soon. However, a fever can make your child uncomfortable. To treat your child's fever at home, your doctor may recommend:

• Plenty of rest. Let your child rest in bed until the fever disappears.
• Plenty of fluids. Encourage your child to drink clear fluids, such as water, ginger ale, lemon-lime soda, clear broth or an electrolyte solution (such as Pedialyte or sports drinks such as Gatorade and Powerade) to prevent dehydration.
• Sponge baths. A lukewarm sponge bath or a cool washcloth applied to your child's head can soothe the discomfort of a fever. However, avoid using ice, cold water, fans or cold baths. These may give the child unwanted chills.

There's no specific treatment for the rash of roseola, which fades on its own in a short time.

Roseola will likely keep your child home for a few days. When staying home with your child, plan low-key activities that you both will enjoy. If your child is sick and you need to return to work, recruit help from your partner or from other relatives and friends.