Three-day fever

Three-day fever is a common, usually harmless viral condition that affects babies and infants. Typical symptoms include a high temperature that lasts for 3 to 5 days followed by a patchy, pale red rash. Doctors also refer to three-day fever as exanthema subitum or roseola infantum. 

As the body loses fluid due to the high temperature, it is important for sick children to have plenty to drink. Antipyretic (fever-reducing) suppositories and warm compresses can also be helpful treatment methods.

Three-day fever is triggered by certain herpes viruses. However, these should not be confused with the pathogens of oral herpes or genital herpes, which also belong to the herpes family.

Three-day fever typically progresses in two phases: a high temperature phase and a subsequent rash. There are also forms with very mild symptoms. In some cases, the condition is barely perceptible. 

High temperature phase 

About 1 to 2 weeks after infection, a high temperature develops, often rising to over 39.5 degrees and generally lasting 3 to 5 days. During the high temperature phase, the affected children can be irritable but otherwise seem little affected. 

In addition to the high temperature, other symptoms are also possible, such as: 

• diarrhea and vomiting  
  
• a cough and a runny nose 
  
• an inflamed throat with red spots on the roof of the mouth and uvula 
  
• swollen lymph nodes in the throat 
  
• swollen eyelids 
  
• in infants, a taut and bulging fontanelle – the soft part of the skull where bone formation is not yet complete  
  

Rash phase 

At the end of the high temperature phase, the body temperature usually returns to normal very quickly. At the same time, a rash with small pink spots or slight nodules that are not usually itchy forms within hours. 

The rash primarily appears on the torso and neck but can also spread to the arms, legs and face. It disappears again after a few days – or in some cases after just a few hours. 

Three-day fever is triggered by certain herpes viruses known as human herpesvirus 6 and, in rarer cases, human herpesvirus 7. The pathogens are also found in healthy people, such as the older siblings or parents of the sick child. The viruses are thought to be primarily transmitted by saliva droplets, for example when coughing and sneezing or during close physical contact. There is no vaccination.

By the age of 3, almost all children come into contact with the pathogens for three-day fever at some point. Only a small number of these develop symptoms. Often, infection has no effect and does not cause any symptoms. Following the infection, the viruses are not completely killed but instead remain in the body for life.

If the immune system becomes very weak, for example in children with cancer, the herpes viruses can become active again. In people with an immune deficiency, complications such as inflammation of the brain (encephalitis) can occur.

Pediatricians diagnose three-day fever on the basis of the typical symptoms: a high temperature that lasts for several days then rapidly disappears followed by a rash. 

If no rash has yet developed, three-day fever is hard to distinguish from other conditions that cause a high temperature. In such cases, doctors may wish to rule out other causes. For example, a urine test can be used to rule out any inflammation of the bladder or kidneys that requires treatment. 

With three-day fever it generally suffices to treat the symptoms. Antipyretic suppositories and warm compresses can help to reduce the high temperature.  

It is important for sick children to drink plenty as babies and infants in particular lose a lot of fluid when they have a high temperature. Water, diluted juice or tea with glucose are suitable choices. If the child refuses to drink, the parents should contact a doctor immediately. 

If the child experiences a febrile seizure during the high temperature phase, he/she should not be held too tightly and should be protected against injury. The first time a child has a febrile seizure in particular, it is important to call the emergency number 112. The emergency doctor will be able to rule out other causes and – if necessary – administer medication to interrupt the seizure.

Febrile seizures can be frightening but are usually medically harmless and do not cause permanent damage.

Further information on febrile seizures and how to treat them can be found at gesundheitsinformation.de.