Gastroenteritis in children: sickness and diarrhoea, dehydration and when to seek help

Gastroenteritis is inflammation of the stomach and bowel, usually from infection, which causes sickness and diarrhoea. The NHS uses the everyday terms diarrhoea and vomiting and says they are often caused by a stomach bug, with food poisoning another common cause. The advice is the same whether a child has diarrhoea and vomiting together or separately.

Two viruses are particularly familiar. The NHS describes norovirus, also called the winter vomiting bug, as a stomach bug that causes vomiting and diarrhoea, usually better in about 2 days, and that it can occur at any time of year. It is caused by a virus that spreads through poo and spreads very easily through close contact, contaminated surfaces, food handled by an infected person and unclean water. It describes rotavirus as an infection that causes diarrhoea and vomiting that is very common, especially in babies and young children, and spreads very easily.

NICE guideline CG84 covers diagnosing, managing and referring infants and young children younger than 5 with acute diarrhoea (lasting up to 14 days) with or without vomiting, including infective gastroenteritis.

The NHS says diarrhoea and vomiting can usually be treated at home. The most important thing is to have lots of fluids to avoid dehydration.

• A pharmacist can advise if a child over 5 has signs of dehydration, such as dark, smelly pee or peeing less than usual, and may recommend oral rehydration powder.

• Children should stay off school or nursery until they have not been sick or had diarrhoea for at least 2 days.

The main danger of gastroenteritis in children is dehydration. The NHS says to call 111 now if you are worried about a baby under 12 months, your child stops breast or bottle feeding while ill, a child under 5 has signs of dehydration such as fewer wet nappies, a child aged 5 or over still has signs of dehydration after oral rehydration sachets, they keep being sick and cannot keep fluid down, there is bloody diarrhoea or bleeding from the bottom, or there is diarrhoea for more than 7 days or vomiting for more than 2 days.

It says to call 999 or go to A&E if a child vomits blood or has vomit that looks like ground coffee, has yellow-green or green vomit, may have swallowed something poisonous, has a stiff neck and pain looking at bright lights, a sudden severe headache or tummy ache, blue, grey, pale or blotchy skin, lips or tongue, severe difficulty breathing or taking lots of quick short breaths, or is confused or not responding as usual. Do not drive to A&E; ask someone to drive you or call 999.

NICE guideline CG84 includes recommendations on assessing dehydration and shock, fluid and nutritional management, antibiotic therapy, escalation of care and information for parents and carers.

Diarrhoea and vomiting can spread easily. The NHS advises staying off school or work until you have not been sick or had diarrhoea for at least 2 days, washing hands with soap and water frequently, washing clothing or bedding with poo or vomit on it separately on a hot wash, cleaning toilet seats, flush handles, taps and door handles every day, not preparing food for other people if possible and not sharing towels, flannels, cutlery or utensils.

For norovirus the NHS notes that alcohol hand gels do not kill the virus, so washing with soap and water is needed, and says not to visit hospitals or care homes until 2 days after symptoms stop.

The NHS says rotavirus is very common in babies and young children. Most children get better in a few days, but some become very dehydrated and need hospital treatment, and very rarely it can be life-threatening. Babies are given two doses of the rotavirus vaccine, at 8 and 12 weeks old, as a liquid squirted into the mouth. If the first dose was missed it can be given up to 15 weeks old and the second up to 24 weeks.

The NHS says a baby should wait until feeling better before having the vaccine if they have a high temperature, diarrhoea or vomiting. A baby cannot have the vaccine if they have had a serious allergic reaction to a previous dose or ingredient, have severe combined immunodeficiency (SCID), or have had a bowel blockage called intussusception or are at higher risk of it.

Diarrhoea and vomiting have many causes. The NHS lists medicines, food intolerance or allergy, irritable bowel syndrome, anxiety, appendicitis, inflammatory bowel disease, coeliac disease and diverticular disease for diarrhoea, and for vomiting pregnancy, migraine, motion sickness, inner ear infections, reflux in babies and other infections such as a urinary tract infection. A child who is not recovering as expected should be seen rather than assumed to have a simple stomach bug.

Most children are looked after at home, with advice available from a pharmacist, NHS 111, a GP or an out-of-hours service. The NHS says 111 can arrange a phone call from a nurse or doctor if needed. Care in hospital for dehydration is free at the point of use.

Private GP services and urgent care clinics also see children with sickness and diarrhoea. The same warning signs apply wherever you are seen, and a child who cannot keep fluids down or who shows signs of dehydration needs prompt assessment.