Your ten-month-old doesn’t look or act very ill, but she suddenly develops a fever between 102 degrees Fahrenheit (38.9 degrees Celsius) and 105 degrees Fahrenheit (40.5 degrees Celsius). The fever lasts for three to seven days, during which time your child may have less appetite, mild diarrhea, a slight cough, and a runny nose, and seems mildly irritable and a little sleepier than usual. Her upper eyelids may appear slightly swollen or droopy. Finally, after her temperature returns to normal, she gets a slightly raised, spotty pink rash on her trunk, which spreads only to her upper arms and neck and fades after just twenty-four hours. What’s the diagnosis? Most likely it’s a disease called roseola— a contagious viral illness that’s most common in children under age two. Its incubation period is seven to fourteen days. The key to this diagnosis is that the rash appears after the fever is gone. We now know that a specific virus causes this condition.
Whenever your infant or young child has a fever of 102 degrees Fahrenheit (38.9 degrees Celsius) or higher for twenty-four hours, call your pediatrician, even if there are no other symptoms. If the doctor suspects the fever is caused by roseola, he may suggest ways to control the temperature and advise you to call again if your child becomes worse or the fever lasts for more than three or four days. For a child who has other symptoms or appears more seriously ill, the doctor may order a blood count, urinalysis, or other tests.
Since illnesses that cause fever can be contagious, it’s wise to keep your child away from other children, at least until you’ve conferred with your pediatrician. Once she is diagnosed as having roseola, don’t let her play with other children until her fever subsides. Once her fever is gone for twenty-four hours, even if the rash has appeared, your child can return to child care or preschool, and resume normal contact with other children.
While your child has a fever, dress her in lightweight clothing. If she is very uncomfortable because of the fever, you can give her acetaminophen in the appropriate dose for her age and weight. Don’t worry if her appetite is decreased, and encourage her to drink extra fluids.
Although this disease rarely is serious, be aware that early in the illness, when fever climbs very quickly, there’s a chance of convulsions. There may be a seizure regardless of how well you treat the fever, so it’s important to know how to manage convulsions even though they’re usually quite mild and occur only briefly, if at all, with roseola.