12418 Stomach Flu

Overview

Stomach flu, also called viral gastroenteritis, is an infection of your stomach and intestines caused by a virus. It is not the same as influenza (the flu), which affects your lungs and airways. It usually causes vomiting and diarrhea, and most people get better on their own within a few days.

Yes, viral gastroenteritis is one of the most common illnesses worldwide. Most people will have it at least once in their lifetime.

It can affect anyone, but young children, older adults, and people with weakened immune systems are more likely to get severe symptoms or complications.

Symptoms

Common symptoms

• Watery diarrhea
• Vomiting and nausea
• Stomach cramps or pain
• Low-grade fever
• Headache and body aches
• Feeling tired or generally unwell

Symptoms in children

• Vomiting and diarrhea that can quickly cause dehydration
• Fewer wet nappies or dry diaper for more than 6 hours
• No tears when crying
• Sunken eyes or soft spot on the top of the head (in babies)
• Unusual sleepiness or irritability

Symptoms in older adults

• Same symptoms as everyone else, but dehydration can come on faster
• Confusion or dizziness
• Weakness or trouble standing
• Dry mouth and lips
• Little or no urination

Causes

Main causes

• Norovirus – the most common cause in adults, often in outbreaks on ships or in schools
• Rotavirus – very common in infants and young children
• Adenovirus and astrovirus – can also cause stomach flu, especially in children

Risk factors

• Living or working in close-contact settings like nursing homes, schools, or daycare centers
• Having a weakened immune system
• Eating food that is not handled or cooked safely
• Not washing hands regularly, especially after using the toilet
• Drinking contaminated water

When to see a doctor

See a doctor urgently if:

• You or your child shows signs of dehydration, like not urinating, dry mouth, dizziness, or confusion
• You see blood in vomit or stool
• You are unable to keep fluids down for 24 hours
• You have severe stomach pain that is getting worse

Book a routine appointment if:

• Symptoms last longer than 3 days
• You have a fever that stays above 101°F (38.3°C) for more than 2 days
• You are pregnant, have an underlying health condition, or care for a young infant
• You feel you need medical advice to be sure it is not something else

Diagnosis

A doctor usually diagnoses stomach flu based on your symptoms, how long they have lasted, and a quick physical exam. They will also check for signs of dehydration.

Tests that may be done

• A stool sample may be sent to the lab if symptoms are severe, if there is blood, or if the infection is part of an outbreak.
• Blood tests are not usually needed but may be done to check for dehydration or electrolyte imbalance.

What to expect at your appointment

The doctor will ask about your symptoms, recent food intake, and any possible exposure to sick people. They will check your abdomen, temperature, heart rate, and skin elasticity. You will likely receive advice on home care and what to watch for.

Treatment

Treatment focuses on replacing fluids and preventing dehydration. The illness usually clears on its own in a few days.

Self-care at home

• Drink small, frequent amounts of water or oral rehydration solution (a special mixture of salts and sugar you can buy at a pharmacy)
• Suck on ice chips if you are vomiting and cannot keep fluids down
• Rest as much as possible, lying on your side if you feel like vomiting
• Eat bland foods when you feel ready, like crackers, toast, rice, or bananas
• Avoid dairy, caffeine, alcohol, carbonated drinks, and very fatty or spicy foods until you feel better
• Wash your hands often and stay home until symptoms have stopped for 48 hours to avoid spreading it

Medical treatments

In some cases, a doctor may recommend medicines to reduce fever, control nausea, or slow diarrhea. These are not given to everyone, and they are usually not safe for children. Antibiotics do not work because stomach flu is caused by a virus. In severe dehydration, a doctor may prescribe fluids given through a vein (intravenous fluids) in a clinic or hospital.

When is surgery considered?

Surgery is not used for stomach flu. If abdominal pain is very severe, surgery could be needed for a different condition, but that is uncommon.

Living with this condition

While you have stomach flu, your main job is to rest and keep drinking fluids. Stay close to a bathroom, and let people around you know so they can help if you need it. Try to rest in a comfortable position, and use a bucket near your bed if you feel sick at night.

Lifestyle tips

• Stay hydrated with small sips of fluid throughout the day
• Use a separate bathroom if possible, or clean shared surfaces after each use
• Wash towels and bedding in hot water
• Avoid preparing food for others until you are fully better
• Get plenty of sleep and take time off work or school

Diet and exercise

When you start to feel hungry, introduce bland, easy-to-digest foods slowly. Frequent small meals are better than three large ones. Avoid heavy exercise until you feel fully recovered, because your body needs energy to heal.

Mental health and emotional wellbeing

Being ill and stuck at home can feel lonely or frustrating. It is normal to feel a little down or anxious, especially if symptoms last longer than expected. Please be kind to yourself and know that this will pass.

Prevention

You can lower your risk of stomach flu with good handwashing, cleaning surfaces, and preparing food safely. There is no vaccine against most causes, but a rotavirus vaccine is given to babies in many countries and helps protect against that specific virus.

Vaccines

The rotavirus vaccine is given to infants in several parts of the world, including the United Kingdom. It does not protect against norovirus or other stomach viruses, so hygiene is still important.

Screening programmes

There is no routine screening for stomach flu. Testing is only done when needed to manage an outbreak or a severe case.

Complications

If left untreated

• Dehydration – the most common complication, which can become severe
• Electrolyte imbalance – low levels of important minerals, which can affect nerves and muscles
• Kidney problems – in rare cases, severe dehydration can lead to kidney injury
• In older adults or babies, complications can happen more quickly and may require hospital care

Long-term outlook

The outlook is very good. Most people recover completely in 1 to 3 days without any lasting problems. For young children and older adults, recovery may take a little longer, but with the right fluids and medical support when needed, nearly everyone gets better.

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