What is exanthema subitum?
Exanthema subitum is also called Three-day fever. As a rule, this is a harmless infection with human herpesvirus 6, or HHV-6 for short, and human herpesvirus 7, or HHV-7 for short. Three-day fever usually occurs in babies or children between the ages of six months and two years. Almost all children have come into contact with these viruses by the time they are three years old. There is no question of seasonality, because the virus occurs all year round.
What are the causes and risk factors of exanthema subitum?
The cause, i.e. the causative pathogens of three-day fever, are the human herpes viruses type 6 and type 7. In the case of HHV-6, there are serotypes A and B as a sub-group . In only about ten to 30 percent of infections, the HHV-7 are the trigger. Three-day fever, which is triggered by HHV-6 , occurs in most babies around the ninth month of life. Three-day fever, which is caused by HHV-7, occurs much later, around 26 months of age.
How contagious is exanthema subitum?
In most cases, the herpes virus, whether type 6 or type 7, is transmitted from person to person via saliva. Thus, the three-day fever is considered to be enormously contagious. Via droplet infection, by talking, coughing or sneezing, the viruses spread rapidly through the air. Even healthy adults or children are considered possible carriers if they have come into contact with the virus. In the very few cases, infection is possible via blood transfusions, organ transplants or breast milk.
The incubation period is about five to fifteen days. In some cases even 17 days. After about 3 days, as the name suggests, not only the fever disappears again, but also the skin rash. From then on, the child is no longer considered contagious.
What are the symptoms of exanthema subitum?
The typical signs of the disease are a sudden fever ranging from 39 degrees to over 41 degrees. The fever remains for the most part for three days and then drops again. In some children, the high body temperature lasts for up to five days.
Skin rash
In about 25 % of affected children, there is a fine blotchy rash all over the body. This rash appears when the fever subsides. The neck and trunk of the body in particular are covered with the exanthema. In many cases, the spots also become large-spotted because they unite. As it progresses, it is possible that the rash spreads and also affects the legs and arms. It can also affect the palate and mucous membranes. In most patients, the rash disappears as quickly as it appeared . At most, two days pass.
Fever and skin rash are not the only signs of exanthema subitum. The following symptoms can also accompany :
- Reddened eardrums,
- Swelling of the eyelids,
- Cough,
- Intestinal inflammation,
- Protrusion of the fontanelle in the infant,
- Swelling of the cervical lymph nodes.
What complications can arise from exanthema subitum?
In many children, about one third of those affected, the high fever leads to a febrile convulsion during the illness. The child twitches with the legs and arms and faints. A febrile convulsion looks bad at first but usually stops after a few minutes . There are no late effects. Nevertheless, a paediatrician should be consulted after a febrile seizure. In some, but rare cases, severe complications can occur during three-day fever, such as pneumonia, liver inflammation, retinitis or even meningitis.
How is exanthema subitum diagnosed?
Every child who suffers from a high fever with an unclear cause should be urgently presented to a paediatrician . It is essential that serious diseases can be ruled out at an early stage . In order for the doctor to determine whether three-day fever is present, he or she will first take a medical history. This is followed by a physical examination of the child. If the disease runs its characteristic course exanthema subitum, it can be easily diagnosed from the symptoms . If the course of three-day fever is atypical, the doctor will take blood and have analysed in the laboratory to make a precise diagnosis. Exanthema subitum can be detected without a doubt using IgM antibodies with the appropriate test. The detection of HHV-6 can be done using a PCR test in urine, blood, cerebrospinal fluid and saliva.
However, it is important to note that the symptoms always match the suspected or positive findings, because people who have had the disease before may also carry traces of the virus.
How is exanthema subitum treated?
Here a purely symptomatic therapy is given. If the child's fever exceeds 38.5 degrees, calf or stomach compresses can help to lower the temperature. After consulting a paediatrician , antipyretics such as paracetamol suppositories may also be given . However, wearing less clothing can also help to lower the fever somewhat. It is essential that the child drinks enough water to prevent dehydration.
If a fever convulsion occurs, this is usually the result of the rapid rise in temperature. In such a case, the child should be placed on the floor . This way, the child can breathe freely and is least likely to injure itself . Even if the seizure was only short-lived and the child was also able to recover, a doctor should be called immediately . In some cases, it is recommended that the child be treated as an inpatient at hospital.
Is there an obligation to report exanthema subitum?
According to the Infection Protection Act, there is no obligation to report three-day fever.
However, it is recommended not to visit facilities such as kindergartens or day-care centres during the illness phase.