What is sixth disease?
Sixth disease is a common infectious disease in young children between 6 months and 3 years old. It is caused by human herpesvirus type 6 (HHV-6). The virus is extremely contagious and is transmitted by coughing. The incubation period (the time between infection and the first signs of illness) is 10 to 15 days. Other names for sixth disease are three-day fever, exanthema subitum and roseola infantum.
What are the symptoms?
The main feature is a high fever that lasts a few days (3 to 5 days) and then falls again quickly. There is often also considerable swelling of the lymph nodes, particularly in the head-and-neck area. Subsequently, countless small red spots arise, initially on the face and shortly afterwards over the trunk. This spotty rash is called a “viral exanthem”. Typical of sixth disease is that the rash does not itch and disappears again after a few days.
How is sixth disease treated?
Treatment is in principle not necessary, because the disease disappears by itself. The most important thing is that the correct diagnosis is made by the doctor, because more serious conditions can also begin with high fever and spots; the appearance of the typical rash can be the key to the right diagnosis.
The difference between fifth and sixth disease
Children with fifth disease (caused by parvovirus B19) usually have less fever and fewer general signs of illness than children with sixth disease.
When to see a doctor
See your GP if a young child has a high or persistent fever, especially before any rash appears, so that the cause can be assessed. Seek urgent care if the child becomes very drowsy or unwell, has a stiff neck, a rash that does not fade under pressure, a fit (febrile convulsion), or difficulty breathing.