Roseola infantum is a common, mild, viral infection that can cause a temperature and rash in babies and young children.
It is caused by a virus from the herpes group, but it does not cause other herpes infections like cold sores. In the past, roseola was sometimes referred to as 'baby measles'.
Roseola usually lasts around four days and almost never requires any medical treatment. Most symptoms are so mild that parents do not even realise their child is infected with the virus.
Roseola commonly affects children aged between six months and two years, and 95% of children have been infected with it by the age of two.
Roseola is contagious before the symptoms appear, so it is difficult to prevent its spread to others.
Signs and symptoms
If your child has roseola, they may have a sudden high temperature, which usually lasts between three to five days. Occasionally, a raised, red rash can develop when your child’s temperature returns to normal.
It appears on the body and spreads to the arms and legs; it is rarely seen on the face. The rash generally lasts for two days and turns white (blanches) when pressed.
Some children get a high temperature but no rash. Rarely, the temperature spikes quite suddenly and can lead to a febrile convulsion (a seizure, or fit). While this is distressing for parents to witness, it is not usually serious.
How is roseola spread?
Roseola is contagious, meaning it can be spread from one person to another.
It is spread by the fluids that are coughed or sneezed into the air.
Children with roseola can only spread the infection before the fever and/or rash occur. Once your child has symptoms, they are no longer contagious.
There is no known way to prevent the spread of roseola and there is no vaccine. Thorough hand hygiene is the best way to help reduce the spread of the virus.
Care at home
Most of the time, roseola does not need any professional medical treatment.
Paracetamol can be used if your child has a high temperature and seems uncomfortable or irritable.
Offer your child plenty of fluids (water, breastmilk or formula) to keep them well hydrated during a fever.
Antibiotics are not given because antibiotics do not treat viruses.
When to see a doctor
You should see your GP if your child:
is lethargic (very sleepy, hard to wake)
has fewer wet nappies than usual
your child has a fever that does not get better after 48 hours has a convulsion (a fit) that lasts less than five minutes
You should call an ambulance immediately if:
l your child has a convulsion that lasts more than five minutes
l your child does not wake up after a convulsion
l If your child is unwell with a fever and a skin rash (small bright red spots or purple spots or unexplained bruises) that does not turn to skin-colour (blanch) when you press on it, this may be a sign of meningococcal infection
Key points to remember
Roseola is a very common, mild infection, usually affecting children between the ages of six months and two years.
Roseola may cause a sudden, high temperature followed by a raised, red rash that lasts for a few days.
Give plenty of fluids to prevent dehydration, and paracetamol may be used to help make your child more comfortable.
Roseola is contagious, but only before the symptoms appear.