Can Constipation Cause a Fever? When Fever With Constipation Needs Attention

01Answer

Does constipation cause fever?

Not directly. Constipation is slow or difficult passage of stools, usually caused by low fibre, low fluid intake, inactivity, changes in routine, medicines or ignoring the urge to go. It can cause abdominal discomfort, bloating and a general feeling of being unwell, and some people feel warm or flushed, but body temperature does not usually rise above 38 °C. A real fever suggests inflammation or infection somewhere in the body.

02Causes

What fever with constipation can mean

• Viral illness: fever, reduced appetite, less drinking and lying in bed slow the bowel; common in children.
• Dehydration during any febrile illness, which hardens stools.
• Urinary tract infection: fever, burning when passing urine, frequency; constipation can also increase the risk of UTIs, especially in children.
• Diverticulitis: pain usually in the lower left abdomen, fever, nausea and change in bowel habit, mainly over age 40.
• Appendicitis: pain starting around the navel and moving to the lower right, fever, loss of appetite and sometimes constipation or diarrhoea.
• Bowel obstruction: cramping pain, swollen abdomen, vomiting and inability to pass stool or wind.
• Severe faecal impaction in frail older people, sometimes with confusion and fever from complications.

03Children

Fever and constipation in children

In young children, a viral infection often causes fever, poor appetite and less drinking, followed by a few days of constipation. This usually resolves as the child recovers and drinks more. However, constipation with fever, crying when passing urine or smelly urine may point to a urinary infection, and abdominal pain that worsens or moves to the lower right needs urgent assessment for appendicitis. Babies under three months with a temperature of 38 °C or more should always be seen urgently.

04Relief

Relieving simple constipation

• Drink plenty of water through the day, more if you have a fever.
• Increase fibre gradually: fruit, vegetables, wholegrains, oats, beans and lentils; see foods high in fibre.
• Prunes, kiwi and pears are particularly helpful.
• Move regularly: walking stimulates the bowel.
• Respond to the urge to go and use a footstool to raise the knees on the toilet.
• A pharmacy laxative such as macrogol or lactulose for a short time if diet is not enough.

See food for constipation for a detailed list.

05Illness

Eating and drinking during a febrile illness

• Prioritise fluids: water, broths, diluted juices and oral rehydration solutions.
• Offer small, frequent, easily digested meals.
• Soft fruits such as pears and kiwi and cooked vegetables add fibre gently.
• Avoid relying only on white bread, rice and dairy for several days, which can worsen constipation.
• Return gradually to a normal high-fibre diet as appetite comes back.

See foods to eat when sick.

06Diverticulitis

Diverticulitis: a common cause in adults

Diverticula are small pouches in the wall of the bowel, common after age 40. When one becomes inflamed or infected, it causes diverticulitis: pain, usually in the lower left abdomen, fever, nausea and changes in bowel habit. Mild cases are managed with rest, fluids and sometimes antibiotics; severe cases need hospital treatment. A high-fibre diet helps prevent symptoms of diverticular disease in the long term; see diet for diverticulitis.

07Prevention

Preventing constipation

• Aim for about 30 g of fibre a day for adults, increased gradually.
• Drink regularly through the day.
• Stay active every day.
• Keep a regular toilet routine, for example after breakfast.
• Review medicines that cause constipation, such as some painkillers and iron supplements, with your doctor.

09Older adults

Older adults

In frail older people, constipation can cause confusion, loss of appetite and urinary retention, and infections may not cause a high temperature. Any sudden change in behaviour needs medical review.

10Summary

Key points to remember

• Simple constipation does not cause a true fever.
• Fever with constipation is usually due to another illness.
• Fluids, fibre and movement relieve simple constipation.
• Fever with abdominal pain needs medical assessment.