Roseola in babies and toddlers: three days of fever, then a rash

Roseola is also called roseola infantum, exanthem subitum, sixth disease and three-day rash. Patient explains it is usually caused by human herpesvirus type 6 and may also be caused by type 7, and that it is rare in adults, probably because childhood infection gives lifelong immunity to most people.

The difficulty is timing. Patient notes roseola is often diagnosed only when the child is getting better, because at first the high fever may cause concern to parents and doctors if it is not clear what is causing it, and other more serious illnesses may need to be ruled out. The sudden drop in fever and the typical rash are reassuring, as they suggest the fever came from the roseola virus and nothing more serious.

The NHS says a child may first have a sudden high temperature and cold-like symptoms such as sore throat, runny nose and cough, loss of appetite, swollen eyelids and swollen glands in the neck. These symptoms last 3 to 7 days before a rash appears. Patient says the temperature can be as high as 40C and the child can be flushed and irritable.

The rash is made up of pinkish-red spots, bumps and small flat areas of discoloured skin, may be harder to see on brown or black skin, starts on the chest, tummy and back before spreading to the neck and arms, and is not usually itchy or uncomfortable. The NHS says it normally fades and disappears within 2 days; Patient adds that it does not usually appear on the face and that some children get similar spots in the mouth.

Some young children have a type of fit called a febrile seizure when they get a sudden high temperature. The NHS says the child may become stiff and twitch, shake or have jerking movements, that it usually lasts 2 to 3 minutes, and that although frightening it is unlikely to harm the child or cause long-term effects. Patient agrees that a fit with the fever is alarming but usually not serious.

The NHS nonetheless says a first seizure, in a child with no previous history of seizures, needs immediate medical attention as a precaution, by calling 999 or going to A&E.

The NHS says to ask for an urgent GP appointment or call NHS 111 if a child:

• is under 3 months old with a temperature of 38C or higher, or you think they have a high temperature

• is 3 to 6 months old with a temperature of 39C or higher, or you think they have a high temperature

• has a high temperature that has lasted 5 days or longer

• is refusing fluids or feeds, or is not their usual self and you are worried

• has a high temperature that does not come down with paracetamol or ibuprofen

• shows dehydration, such as nappies that are not very wet, sunken eyes and no tears when crying

The NHS says to call 999 or go to A&E if a baby or young child has blue, grey, pale or blotchy skin, lips or tongue; a rash that does not fade when a glass is rolled over it (the same as meningitis); difficulty breathing, including grunting, the stomach sucking under the ribcage, breathlessness or very fast breathing; a weak, high-pitched cry that is not their normal cry; is not responding as normal or not interested in feeding; is sleepier than normal or hard to wake; or has an unexpected seizure. The NHS also says to speak to a GP if a person with a weakened immune system has had contact with someone with roseola, because it can be serious for them.

There is no treatment that kills the virus, says Patient; care aims to keep the child comfortable. The NHS advice is to let the child rest, make sure they drink lots of fluids, use children's paracetamol or children's ibuprofen if the temperature makes them uncomfortable (checking the dose on the bottle), and keep them at home while the temperature is high, which is when roseola is thought to be most contagious.

The NHS also says not to cover the child in too many clothes or bedclothes, not to give aspirin to under-16s, not to combine ibuprofen and paracetamol unless a GP says to, not to give paracetamol under 2 months, and not to give ibuprofen under 3 months or under 5kg or to children with asthma. Patient adds that cold-sponging is no longer advised, and suggests giving paracetamol first if a child will not drink, then offering a drink some time later when the temperature has come down.

Patient says roseola spreads from person to person through saliva, with an incubation period of 9 to 15 days, and that the child is probably infectious throughout the illness and perhaps before the fever appears. Once the fever has settled, the NHS says there is no need to keep a child at nursery away if they feel well enough. Roseola does not appear in the UKHSA exclusion table for children's settings.