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Gastroenteritis

Expert reviewer, Dr Adrian Raby, General Practitioner
Next review due February 2021

Gastroenteritis is inflammation of your stomach or bowels (your gastrointestinal tract). The name gastroenteritis covers a range of conditions, including ‘tummy bugs’, ‘food poisoning’ and ‘traveller’s diarrhoea’. Gastroenteritis is usually caused by an infection.

A family eating breakfast

About gastroenteritis

Gastroenteritis usually gives you diarrhoea and/or vomiting and can cause pain in your abdomen (tummy).

You can get gastroenteritis by eating or drinking food that has bacteria, viruses or parasites in it. You can also catch gastroenteritis from another person with it, or by touching objects and surfaces around them.

The infections that cause gastroenteritis can inflame the lining of your gut and stop it working as it should, causing diarrhoea. In most cases you never know for sure which bug is causing your gastroenteritis. Treatment tends to be similar whichever bug it is.

Gastroenteritis is really common. In the UK, about one in five people get gastroenteritis each year. The illness is more common in young children, who may have it more than once a year.

If you have gastroenteritis, you’ll usually recover and feel better within a few days to a week and won’t need medical treatment. Parents and carers of children with gastroenteritis often find they can look after their child at home, without needing medical advice.

However, if a baby or young child has severe diarrhoea or vomiting, they can become dehydrated and may need medical attention. For more information, see our section below on when to seek medical help and our FAQ on spotting dehydration in your child.

Symptoms of gastroenteritis

The time between catching the infection and the start of your symptoms (the incubation period) depends on the type of infection you have. It's usually between one and three days, but symptoms can sometimes come on faster or slower than this.

Symptoms of gastroenteritis usually include:

  • diarrhoea, which may be very watery, or contain blood or mucus
  • feeling sick or vomiting
  • abdominal cramps, bloating, stomach rumbling or abdominal pain

You may also have:

  • a raised temperature
  • loss of appetite
  • muscle aches
  • headaches

These symptoms can sometimes be caused by other problems, such as other types of infections, irritable bowel syndrome, inflammatory bowel disease or side-effects of medicines. However, these will usually cause symptoms that last for a lot longer than gastroenteritis.

For children with gastroenteritis, diarrhoea may last five to seven days and stop within two weeks. Vomiting usually lasts for one to two days, stopping within three days. If you’re concerned or your child appears unwell, seek medical advice.

Diagnosis of gastroenteritis

If you think you or your child has gastroenteritis, it’s best to keep away from doctors’ surgeries and hospitals so as not to spread the infection to others. See our section below on when to seek medical help by contacting your GP surgery.

The surgery will probably get one of their GPs to phone you. They’ll ask questions to help them assess how unwell you are, whether they need to see you and what treatment you may need. They may ask you:

  • how often you’ve vomited
  • about your diarrhoea – how often you’ve had a bowel movement and the consistency
  • whether you’ve any blood in your faeces (stool)
  • whether you’ve been able to keep down any food or drink, and how much fluid you’ve been able to drink
  • whether you’ve had contact with someone who has had similar symptoms
  • whether you’ve been abroad recently
  • about your medical history and other medical conditions you may have

If your GP does need to see you, they’ll probably check your temperature, blood pressure, heart rate and how quickly you’re breathing. They’ll check whether your abdomen is tender and look for signs that you may have become dehydrated.

Your GP may ask for a sample of your faeces to send for laboratory testing, although this isn’t usually necessary.

Treatment of gastroenteritis

Self-help for gastroenteritis

If you have gastroenteritis, you may well have an infection that you could pass on to others. Stay at home and don’t go into work for at least 48 hours after the diarrhoea and vomiting have stopped. If your child has gastroenteritis, keep them off school or nursery until 48 hours after they’re clear of diarrhoea and vomiting. See our section on preventing gastroenteritis below for other precautions you should take.

Most people with gastroenteritis can recover at home and won’t need any special medical treatment. But see our section below about when you should call for medical help.

If you’re taking regular medicines then, in most cases, you should continue to take them as usual. However, for some medicines the advice may be different. So, if you have diarrhoea and/or vomiting you should read the patient information leaflet that comes with your medicine carefully. You should also read this information if you’re taking the contraceptive pill, as vomiting and diarrhoea can affect how well it works. If you need advice about taking your medicines, ask your pharmacist.

The time it takes to recover depends on which infection you have. Some viral infections only last a day or two, while other infections can take a week or even longer to recover from.

What to eat and drink

If you have diarrhoea and vomiting your body will be losing more fluid than usual. You need to make sure you replace this by having plenty to drink (keep hydrated).

Drinks such as water or squash will help to keep you hydrated. If your baby has gastroenteritis, they should continue to breastfeed or be given their other milk feeds. It’s best not to give young children fruit juices or fizzy drinks while they’re unwell.

Once you’re hydrated, have small, light meals when you feel hungry, but don't have fatty or spicy foods.

Probiotics

Certain probiotics (supplements or foods such as live yoghurts containing ‘good’ bacteria) may help to reduce how long you have diarrhoea. See our FAQ below for more information.

Oral rehydration solutions

Oral rehydration solutions can help your body to replace lost water. Most people can recover from gastroenteritis without needing an oral rehydration solution. However, in some circumstances your GP may recommend taking them. They can be particularly helpful for:

  • people over 60
  • people who are frail or have other illnesses
  • young children

Oral rehydration solutions come as a powder that you add to water to make a drink. They have the right mix of sugars and electrolytes (minerals and salts) to help you replace lost water and salt. Sports drinks don’t have this right mix so it’s best not to use them for rehydration, especially in young children.

Medicines

Most people with gastroenteritis don’t need medicines.

Medicines to stop diarrhoea, such as loperamide, aren’t usually necessary. They’re only suitable for adults and children over 12. These medications only prevent diarrhoea temporarily, but they can be useful in some situations, for example if you need to travel. Don’t take these medicines if you have blood or mucus in your faeces or if you have a high temperature, as they could make you more ill.

If you have severe vomiting, your GP may prescribe you a medicine called an antiemetic to help stop this.

Your GP won’t usually prescribe antibiotics unless they know for sure they’re needed. In most cases of gastroenteritis antibiotics aren’t needed, and won’t help. If your GP thinks you may have a type of gastroenteritis needing antibiotics, they’ll probably ask you to provide a sample of your faeces (stool). Antibiotics may be prescribed based on the laboratory results.

Hospital treatment

If you become very dehydrated or unwell, you may need to be admitted to hospital. In hospital, you can be given fluid directly into your bloodstream through a fine tube put into your vein (intravenously) to rehydrate you.

Causes of gastroenteritis

There are many different causes of gastroenteritis. The main cause of gastroenteritis is an infection with a virus, bacteria or parasite. Less commonly, you can get gastroenteritis as a side-effect of some medicines or from eating toxins.

Viruses

Viruses are a common cause of gastroenteritis, particularly in children. These include:

  • rotavirus – this is the most common cause of gastroenteritis in young children
  • norovirus – this is very contagious, and often causes outbreaks of gastroenteritis in groups of people
  • adenovirus – this is another common cause of gastroenteritis in young children

Viral infections can be seasonal, meaning they happen more often at certain times of year. For example, more people get norovirus infections during the winter and spring.

Bacteria

Bacteria that can cause gastroenteritis are most commonly caught from eating contaminated food. Different bacteria that cause food poisoning include Salmonella, Campylobacter and Escherichia coli (E. coli). They tend to be caught from eating food or drink that’s not properly handled, prepared or stored.

Parasites

There are three main parasites which can cause gastroenteritis. These are called Cryptosporidium, Entamoeba and Giardia. Parasites are less likely to cause gastroenteritis in the UK than viruses or bacteria. You might pick them up when travelling abroad or from animals.

Toxins

Toxins include some metals, some fungi and chemicals produced by certain bacteria and fish.

Getting gastroenteritis

You can pick up an infection in different ways. These include:

  • eating raw, undercooked or contaminated food, such as meat, shellfish or unpasteurised milk
  • from another person – usually by direct contact (eg traces of faeces on unwashed hands) or by touching surfaces they’ve touched
  • by drinking contaminated water, particularly in countries that lack clean drinking water
  • touching an infected animal

If you take antibiotics, you may also be more likely to get diarrhoea. This is because antibiotics can upset the natural balance of bacteria in your gut, letting an infection take hold. Antibiotics can also sometimes directly cause diarrhoea.

For more information on getting gastroenteritis, have a look at our section below on prevention, and our FAQ on avoiding gastroenteritis when abroad. You may also find it helpful to see our information on food hygiene.

Complications of gastroenteritis

One of the main complications of gastroenteritis, especially in children, is dehydration. This happens when lots of fluid is lost through vomiting and diarrhoea and you don’t drink enough liquid to make up for it. Vomiting and diarrhoea can also make the electrolytes (salts and minerals) in your body get out of balance. Being severely dehydrated can be dangerous. For more information, see our FAQ below on the signs of dehydration in children.

Other possible complications of gastroenteritis include:

  • lactose intolerance, which causes sensitivity to dairy products, although this is usually only temporary
  • reactive arthritis or other autoimmune conditions, where your body’s immune system mistakenly attacks your own tissues. This only usually happens following bacterial gastroenteritis
  • haemolytic uraemic syndrome, which can cause serious kidney problems
  • irritable bowel syndrome (IBS)

Young children are more likely to get complications than adults. You’re also more likely to get complications from gastroenteritis if:

  • you’re elderly
  • you have other health problems
  • you have a weak immune system

When to seek medical help for gastroenteritis

Most people with gastroenteritis will recover at home and don’t need any special medical advice or treatment. However, contact your GP if you have gastroenteritis and you:

  • are vomiting a lot but can’t keep down any fluids
  • have blood in your diarrhoea
  • have a fever
  • have had diarrhoea for more than 10 days
  • can’t control your bowels
  • have signs of dehydration, such as a dry mouth, muscle cramps, passing little urine, sunken eyes, confusion or irritability
  • have recently travelled abroad
  • have other long-term conditions, such as a lowered immune system, diabetes or inflammatory bowel disease
  • don’t have someone who can look after you at home and your symptoms are severe or you’re elderly

It’s important to seek medical help if you think your child with gastroenteritis is dehydrated. See our FAQ below on what to look out for.

Preventing spread of gastroenteritis

To reduce your chance of getting or spreading gastroenteritis, follow these tips.

  • Always wash your hands with soap and water after going to the toilet or changing your baby’s nappy.
  • Always wash your hands before and after preparing or eating food.
  • Wash soiled clothing or bed linen separately from other laundry and at the highest temperature possible (60°C or higher if possible). Only half fill the washing machine, so that everything is thoroughly cleaned and rinsed.
  • Clean toilet seats, flush handles, taps, surfaces and door handles daily with hot water and detergent. If you have a disinfectant, use this to clean the toilet. Use a cloth that can be thrown away or one that is only used for this purpose.
  • Don't share towels and flannels.
  • Stay off work for 48 hours after your diarrhoea or vomiting has stopped.
  • Don’t go swimming for at least two weeks after your diarrhoea has stopped if you’ve been diagnosed with a parasite called Cryptosporidium.

If you have gastroenteritis, stay away from hospitals and doctors’ surgeries if possible. This is so you don’t spread it to people who are at high risk of complications.

Young babies are now offered immunisation against rotavirus, a common cause of gastroenteritis. This is given in two doses – the first at two months and the second at three months. It’s given as drops into their mouth.

Before travelling abroad, check what precautions you should take for the country you’re travelling to at www.travelhealthpro.org.uk. You may need vaccinations or to drink bottled water, for example.

To find out more about how to avoid gastroenteritis when preparing meals, see our information on food hygiene.

Frequently asked questions

  • Be careful about what you eat and drink while on holiday to reduce your chance of getting ill. Infections can be picked up from contaminated food and water. While away, be especially careful by:

    • eating at restaurants with a good hygiene reputation
    • being cautious about eating food from street vendors and buffets
    • choosing food that is served piping hot
    • avoiding raw vegetables or food that has been left out
    • eating fruit that you have peeled yourself
    • avoiding ice (unless you know it is made from clean water)
    • drinking water and other drinks from bottles only (with an intact seal); boiling or chemically purifying water after using a reliable filter

    Before travelling abroad, plan what you can take with you in case you become ill. You may wish to take oral hydration salts or anti-diarrhoea tablets.

    Also, make sure you get any travel vaccinations that you need before you go. Book an appointment at your GP surgery or a travel clinic four to six weeks before you travel. However, if you’re travelling sooner, it’s still worth booking an appointment.

    If you have any questions or concerns, talk to your travel health adviser, GP surgery or pharmacist before you go abroad. There’s also a lot of information online about keeping yourself healthy while abroad, including from TravelHealthPro.

  • Gastroenteritis can cause babies and children to become dehydrated quickly, which can be dangerous. You should contact your GP if you think your child may be becoming dehydrated.

    Symptoms and signs of dehydration include:

    • being irritable and tired
    • passing water (urinating) less
    • loss of skin elasticity – when gently pinched, the skin doesn't immediately spring back into position
    • dry mouth
    • sunken eyes
    • faster than usual heart rate
    • rapid, shallow breathing

    If your child’s dehydration gets worse and they go into what doctor’s call ‘shock’:

    • their skin may become pale or mottled
    • they may have cold fingers and toes
    • they may not be fully conscious
    • blood may take longer to return to hands or feet when gently squeezed

    Make sure your child gets immediate medical attention if they have these signs of shock – they may need to be admitted to hospital.

  • Bacteria are often thought of as harmful and a cause of illness, but there are many good bacteria that can help to keep your gut healthy. Probiotics are ‘good’ bacteria found in certain foods (such as live yoghurts) and food supplements.

    Good bacteria in your gut help to prevent harmful organisms from growing there. Gastroenteritis is usually caused by harmful bacteria, viruses or parasites. Probiotic bacteria such as Lactobacillus might help to correct the balance of bacteria in your gut. This might help to relieve symptoms of diarrhoea and speed up your recovery. They might also help to prevent some types of gastroenteritis, such as traveller’s diarrhoea.

    However, more research is needed before we can be sure, because not all studies have found that probiotics made a difference.

    Doctors think it’s generally safe to take probiotics. However, they’re best avoided if you’re very unwell or if you have a lowered immune system.


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Related information


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    • Personal communication Dr Adrian Raby, General Practitioner, 2018
  • Reviewed by Dr Kristina Routh, Freelance Health Editor, February 2018
    Expert reviewer, Dr Adrian Raby, General Practitioner
    Next review due February 2021



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