Roseola: symptoms, how long it lasts and what to do

Roseola is an infection of early childhood. The NHS describes it as very common, usually causing a high temperature and a rash, and mainly affecting babies and toddlers. The NHS says you can normally look after your child at home and that they should recover within a week.

The NHS says roseola is thought to be most contagious while the temperature is high. The rash comes at the end of the illness, after those first days of fever.

Because the first sign is a fever that may have no obvious cause, roseola is often only recognised in hindsight, after the rash arrives.

The NHS advice is to let your child rest, make sure they drink plenty of fluids, and give children's paracetamol or children's ibuprofen if the high temperature is making them uncomfortable, checking the dose on the bottle. Keep your child at home while their temperature is high.

The NHS fever-in-children page adds that a high temperature is a natural response to infection. It advises against undressing or sponging a child to cool them, against too many clothes or bedclothes, and against alternating ibuprofen and paracetamol unless a health professional tells you to.

Do not give aspirin to under-16s. The NHS also says not to give paracetamol to a child under 2 months, and not to give ibuprofen to a child under 3 months or under 5kg, or to children with asthma unless a doctor has recommended it.

The NHS lists the early symptoms as a sudden high temperature, cold-like symptoms such as a sore throat, runny nose and cough, loss of appetite, and swollen eyelids and swollen glands in the neck. These last 3 to 7 days before a rash appears.

The rash is made up of pinkish-red spots, bumps and small flat areas of discoloured skin. It starts on the chest, tummy and back, then spreads to the neck and arms. It is not usually itchy or uncomfortable and normally fades within 2 days. It may be harder to see on brown or black skin.

The NHS says you can normally look after your child at home and that they should recover within a week. The illness has a recognisable timeline: the first symptoms, a sudden high temperature and cold-like symptoms, last 3 to 7 days before a rash appears, and the rash is not usually itchy or uncomfortable and normally fades and disappears within 2 days.

The NHS says to speak to a GP or call NHS 111 if the high temperature has lasted 5 days or longer, as that is one of the triggers for urgent advice.

The NHS says to keep your child at home while the temperature is high, as this is when roseola is thought to be most contagious. After that, a child who feels well enough can return to nursery. There is no need to wait until the rash has disappeared.

That differs from some other childhood rashes, so it is worth checking rather than assuming. If you are unsure whether a rash is roseola, measles or another infection, get it assessed before sending your child to a setting with young babies or anyone who is immunosuppressed.

Fever in a very young baby needs particular care. The NHS says to ask for an urgent GP appointment or call NHS 111 if a child is under 3 months and has a temperature of 38C or higher, or is 3 to 6 months and has 39C or higher. The same applies if you think they have a high temperature.

Other triggers for urgent advice include a high temperature lasting 5 days or longer, refusing fluids or feeds, signs of dehydration such as few wet nappies, sunken eyes and no tears, a temperature that does not come down with paracetamol or ibuprofen, or a child who is not their usual self and you are worried.

If your child or you have a weakened immune system and have been in contact with someone with roseola, the NHS says to speak to a GP, because it can be serious.

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, difficulty breathing, a weak, high-pitched cry, unresponsiveness, unusual sleepiness or difficulty waking, or an unexpected seizure. The non-fading rash matters because it can be a sign of meningitis.

Febrile seizures happen when a child has a sudden high temperature. The NHS says the child may stiffen, twitch or shake, and that these usually last 2 to 3 minutes and rarely more than 10. They usually affect children aged between 6 months and 6 years, and are unlikely to harm the child or cause long-term effects.

Even so, call 999 or go to A&E if it is the first seizure, lasts more than 5 minutes, involves breathing difficulty or one-sided stiffness, or happens more than once in 24 hours. During a seizure, note the time, protect the head, clear dangerous objects, and afterwards use the recovery position. Do not hold the child down or put anything in the mouth.

Roseola's signature is that the rash appears after the fever settles, not during it. A rash that arrives with the fever, spreads quickly or does not fade under pressure is a different situation. The NHS fever page says to call NHS 111 if a child has other signs of illness, such as a rash, along with a high temperature.

A GP may diagnose roseola from the history and the timing of the rash. If your child is very unwell, has had a febrile seizure for the first time, or the picture is unclear, hospital assessment may include blood and urine tests and occasionally a lumbar puncture, as the NHS febrile seizure page describes.