Medically known as roseola infantum, the three-day fever is a very common childhood disease, affecting infants or young children up to age three. The name three-day fever refers to the first three days of fever, followed by a characteristic rash while the fever subsides.
Roseola is more common in the spring and fall, occasionally causing minor outbreaks.
In the US, an estimated 40% of children get this infection by the age of one year, 77% by age two. By the time they entered the school, most children have had the infection.
Causes and risk factors
Roseola is usually caused by herpesvirus-6 (HHV-6), and in rare cases by herpesvirus-7 (HHV-7), two of the many herpes viruses known to infect humans. For example, other herpes viruses cause chickenpox and shingles.
Female gender and having older siblings are considered risk factors for getting this infection.
This virus is spread from one person to another, usually through saliva, for example if the child with infections shares food from a plate, coughs or sneezes. The child with roseola is no longer contagious one day after their fever is gone.
Signs and symptoms
The incubation period is between five and 15 days. As the name implies, the three-day fever causes a high fever of 103 to 105F (39.5 to 40.5C). Despite the high fever, the children with roseola are typically alert and active.
Seizures may occur in 10 to 15% of the cases, especially if the fever starts suddenly and rises quickly. In this case, the child may lose consciousness briefly, fall down and have jerking movements of their arms and legs for seconds to minutes.
After three days, the fever subsides, and a rash appears in about one in three children with this infection. The rash mostly affects the chest and abdomen, but can appear on the face, arms and legs as well.
The rash is flat, pink-red and turns white when pressed and some spots and patches may have a whitish ring around them. The rash is not itchy and may last from a few hours to two days.
Some children may have pink or red spots (known as Nagayama spots) at the back of the throat and on the uvula, which is the little flap of tissue that hangs at the back of the throat.
In some cases, the child may have a runny nose or complain of a sore throat or stomach discomfort. The lymph nodes in the head and neck areas may become enlarged.
Most infections resolve in about one week. Younger children may also be more irritable, have swollen eyelids, a decreased appetite and a mild diarrhea. Some children get the infection, but do not develop any symptoms.
In rare cases, roseola may complicate with inflammation of the liver (hepatitis) or inflammation of the brain (encephalitis).
Like other herpes viruses, the virus that causes roseola remains latent in the body. This virus may reactivate later on in life and cause complications in individuals with weak immune systems or those who have had organ transplants.
Although more research is needed, some scientists suggest a possible association between this infection and multiple sclerosis, chronic fatigue syndrome and lymphoma.
Roseola rash versus measles rash
A doctor may need to rule out other childhood diseases like measles, because both infections cause rashes, and measles can cause more complications. One way to differentiate these two infections is by looking at the rash.
The roseola rash is pink or red, starts on the chest and back and spreads to the extremities and face. The spots are flat, surrounded by a white ring. The rash starts after the fever is gone and clears up within three days.
The measles rash is reddish brownish and spreads from the face down to the other part of the body. The spots create a blotchy, bumpy appearance. After the rash appears, a high fever may develop and the rash tends to last longer, about five to six days.
Additionally, children with roseola usually appear well and alert and the disease resolves in one week. Children with measles usually look sicker and the disease may last up to two weeks.
The diagnosis is based on the symptoms in most cases. Culture and serologic tests are available in case the doctor needs to confirm the diagnosis, but these tests are rarely needed. Some tests are recommended if the child has seizures. PCR (polymerase chain reaction) tests are used to detect virus reactivation.
Treatment for three-day fever
Many parents seek medical treatment, because of the high fever and seizures caused by the infection. However, the seizures do not require special treatment in most cases. Febrile seizures tend to be short lived and are rarely dangerous.
Acetaminophen (Tylenol) and ibuprofen (Advil) can be used for fever.
In severe cases, the doctor can recommend antiviral drugs like ganciclovir or foscarnet.
Aspirin should not be used due to potential risk of Reye’s syndrome, a rare but potentially serious condition.
It is important that the child gets enough rest and drinks plenty of water to prevent dehydration. Electrolyte solutions such as Pedialyte can be useful. Lukewarm baths and cold cloths on the forehead will provide comfort during fever.
Parents should call the doctor right away if the child develops seizures. A doctor should also be consulted if the child has a fever over 103F (39.4C), if the rash lasts longer than three days or if the fever comes back.
Three-day fever prevention
Like other infections spread through saliva or respiratory droplets, roseola can be prevented by washing your child’s hands often, and by avoiding the sharing of food plates or cups.
Older children can learn how to sneeze and cough in a tissue. Regular disinfection of surfaces at home helps prevent the spread of many germs, including herpesviruses.
There is no vaccine to protect against roseola and most children have antibodies by the time they start going to school. Younger children should stay at home when they have high fever.
It is possible to get this infection more than once, but this is unusual. Overall, the prognosis is very good. The three-day fever is a mild, self-limited disease in most cases. It goes away in about one week with no long-term complications.
Gorman, C.R., editor James, W.D. Roseola infantum. Medscape.
Gorman, C.R., editor James, W.D. Roseola Infantum Clinical Presentation. Medscape.
Tesini, B.L. (2021). Roseola Infantum. Merck Manual.