Diarrhoea is the passing of frequent loose or liquid stools (faeces) three or more times a day.
When this change to the stools starts suddenly and lasts for less than two weeks, the condition is known as acute diarrhoea.
If it lasts more than two weeks, it is called persistent diarrhoea.
If it lasts more than four weeks it is called chronic diarrhoea.
Diarrhoea usually occurs when fluid cannot be absorbed from the contents of your bowel, or when extra fluid is secreted into your bowel, causing watery stool.
Diarrhoea is usually a symptom of gastroenteritis (a bowel infection), which can be caused by:
- a virus – such as norovirus or rotavirus
- bacteria – such as campylobacter, Clostridium difficile (C. difficile), Escherichia coli (E. coli), salmonella or shigella; these can all cause food poisoning.
- parasites – such as the Giardia intestinalis parasite that causes giardiasis
Other possible causes of short-term diarrhoea include:
- feelings of anxiety
- drinking too much alcohol
- a food allergy
- damage to the lining of the intestines as a result of radiotherapy
Diarrhoea can also sometimes be a side effect of a medication, including:
- antacid medicines that contain magnesium
- some chemotherapy medicines
- non-steroidal anti-inflammatory drugs (NSAIDs)
- selective serotonin reuptake inhibitors (SSRIs)
- statins (cholesterol-lowering medicines)
- laxatives (medicine used to help empty your bowels)
Conditions that can cause persistent diarrhoea include:
- irritable bowel syndrome (IBS) – a poorly understood condition affecting the normal functions of the bowel
- inflammatory bowel disease – conditions that cause the gut to become inflamed, such as Crohn’s disease and ulcerative colitis
- coeliac disease – a digestive condition where you have an adverse reaction to gluten
- chronic pancreatitis – inflammation of the pancreas
- diverticular disease – where small bulges or pockets develop in the lining of the intestine
- bowel cancer – this can cause diarrhoea and blood in your stools
Persistent diarrhoea can also sometimes occur following surgery on the stomach, such as a gastrectomy. This is an operation to remove part of the stomach – for example, as a treatment for stomach cancer.
Symptoms associated with diarrhoea
Diarrhoea is where you frequently pass watery or loose stool. Some people may also have other symptoms, depending on the cause.
Associated symptoms can include:
- abdominal pain & cramps
- change in colour of your stools
- nausea and vomiting
- loss of appetite
- general body weakness and tiredness
The excessive loss of water in your stool can also sometimes lead to dehydration, which can be serious if not recognised and treated quickly.
Symptoms of lack of fluid in the body (dehydration)
Diarrhoea and vomiting may cause dehydration. Consult a doctor quickly if you suspect you are becoming dehydrated. Mild dehydration is common and is usually easily and quickly reversed by drinking lots of fluids. Severe dehydration can be fatal unless quickly treated. This is because the organs of your body need a certain amount of fluid to function.
Signs of dehydration
Signs of dehydration in children can include:
- irritability or drowsiness
- passing urine infrequently
- pale or mottled skin
- cold hands and feet
- they look or feel increasingly unwell
Signs of dehydration in adults can include:
- tiredness and a lack of energy
- loss of appetite
- feeling lightheaded
- dry mouth & tongue
- sunken eyes
- muscle cramps
- rapid heartbeat
- passing little urine.
- becoming irritable.
Symptoms of severe dehydration in adults include:
- Rapid heart rate.
- A greatly reduced amount of urine that you make.
This is a medical emergency and immediate medical attention is needed.
Dehydration in adults with acute diarrhoea is more likely to occur in:
- Elderly or frail people.
- Pregnant women.
- People with severe diarrhoea and vomiting. In particular, if you are not able to replace the fluid lost with enough drinks.
Seek medical advice
Seek medical advice if you have diarrhoea for more than three to four days, or if you have diarrhoea with any of the following:
- had six or more episodes of diarrhoea in the past 24 hours (in case of children)
- diarrhoea and vomiting at the same time (in case of children)
- Blood in your stool
- Dark-black stool that looks like tar (but tell your doctor if you have been taking over-the-counter medications, which also can make the stool look darker than usual)
- Mucus passed with no stools
- Abdominal pain
- Rectal pain
- Recent travel abroad
- Recent seafood consumption
- Reason to believe that you have food poisoning
- Family members who have similar illness
- Colleagues, associates or friends who have similar symptoms after eating in the same venue
Do I need any tests?
Most people with acute infectious diarrhoea do not need to see a doctor or seek medical advice. Symptoms are often quite mild and commonly get better within a few days without any medical treatment.
However, in some circumstances, you may need to see a doctor. The doctor may ask you various questions – for example, about:
- Recent travel abroad.
- Whether you have been in contact with someone with similar symptoms.
- Whether you have recently taken antibiotics.
- Whether you have recently been admitted to hospital.
This is to look for possible causes of your diarrhoea. The doctor will also usually examine you, especially looking for signs of lack of fluid in the body (dehydration).
- Tests are not usually needed. However, if you are particularly unwell, have bloody stools (faeces), have recently travelled abroad, are admitted to hospital, or your symptoms are not getting better, your doctor may ask you to collect a stool sample.
Diarrhoea will usually clear up without treatment after a few days, particularly if it’s caused by an infection.
It’s important to drink plenty of fluids to avoid dehydration, particularly if you are also vomiting. Take small, frequent sips of water.
Oral rehydration solutions (ORS)
Suggest to using an oral rehydration solution (ORS) to prevent dehydration if you are at risk – for example, if you are frail or elderly.
Eat small, light meals and avoid fatty or spicy foods.
Antidiarrhoeal medicines may help reduce your diarrhoea and slightly shorten how long it lasts. However, they are not usually necessary.
Loperamide is the main antidiarrhoeal medicine used, because it has been shown to be effective and causes few side effects. Loperamide slows down the muscle movements in your gut so that more water is absorbed from your stools. This makes your stools firmer and they are passed less frequently.
Do not take antidiarrhoeal medicines if there is blood or mucus in your stools and/or you have a high temperature (fever). Instead, you should contact your doctor for advice.
Most antidiarrhoeal medicines should not be given to children.
Painkillers will not treat diarrhoea, but paracetamol or ibuprofen can help relieve a fever and a headache.
If necessary, you can give your child liquid paracetamol or ibuprofen.
Treatment with antibiotics is not recommended for diarrhoea if the cause is unknown. This is because antibiotics:
- will not work if the diarrhoea is caused by a virus
- can cause unpleasant side effects
- can become less effective at treating more serious conditions if they are repeatedly used to treat mild conditions
Antibiotics may be recommended if you have severe diarrhoea and a specific type of bacteria has been identified as the cause.
They may also be used if you have an underlying health problem, such as a weakened immune system.
Occasionally, hospital treatment may be needed if you or your child is seriously dehydrated. Treatment will involve administering fluids and nutrients directly into a vein (intravenously).
How can I prevent diarrhoea?
The most important way to avoid diarrhoea is to avoid coming into contact with infectious agents that can cause it. This means that hygienic food preparation and storage techniques, and good hand washing, especially when preparing food and after using the toilet are very important.
If someone in your home has diarrhoea, take precautions to stop it spreading:
- Disinfectant the toilet, handle and the seat after the person has used it each time.
- Don’t share towels, flannels, cutlery or utensils with the person who is unwell.
- Keep them at home until at least 48 hours after the last episode of diarrhoea.