Pale stools: causes, red flags and when to get it checked

Bile, made in the liver and stored in the gallbladder, is released into the small bowel to digest fat and gives stool its colour. When flow is blocked or the liver is unable to produce bile, stool becomes pale and urine darkens as bilirubin builds up in blood and is excreted through the kidneys.

• Gallstones lodged in the bile duct, with pain, jaundice and sometimes fever.

• Medicines: some antibiotics, antacids with aluminium, anti-diarrhoeal bismuth products, the oral contraceptive and paracetamol overuse.

• Hepatitis and other liver inflammation, from viruses, alcohol or autoimmune causes, with fatigue, nausea and jaundice.

• Pancreatitis and pancreatic insufficiency, causing pale, fatty, floating stools.

• Primary biliary cholangitis and primary sclerosing cholangitis, with itching and abnormal liver tests.

• Cirrhosis and alcohol-related liver disease.

• Narrowing of the bile duct, pancreatic cancer, bile duct cancer or ampullary tumours, with painless jaundice and weight loss.

• Coeliac disease and other malabsorption conditions, causing fatty pale stool.

Yellowing of skin or eyes, dark urine, severe itching, abdominal pain, fever and rigors, unintended weight loss, loss of appetite, tiredness, vomiting or a family history of liver disease or pancreatic cancer need urgent assessment.

• Call 999 or go to A&E: pale stools with severe abdominal pain, high fever with rigors, confusion or vomiting blood.

• Same-day GP or NHS 111: jaundice with pale stools, or fever and abdominal pain.

• Urgent GP: persistent pale stools with dark urine, itching or weight loss.

• GP within days: a single pale stool after a known cause that does not return to normal.

The doctor asks how long, urine colour, itching, pain, fever, appetite, weight change, alcohol, medicines, supplements, travel and infection risks, and family history. They examine for jaundice, an enlarged liver or gallbladder, tenderness, ascites and signs of chronic liver disease.

• Liver function tests with bilirubin, ALP, GGT and ALT: the first line to show a bile duct blockage pattern.

• Abdominal ultrasound: to look for gallstones and dilated bile ducts.

• MRCP or CT scan: to image the bile and pancreatic ducts and look for masses.

• Viral hepatitis and autoimmune markers: for liver inflammation.

• ERCP: for diagnosis and treatment of duct stones or narrowing.

Pale stools need medical attention rather than self-care. In the meantime, avoid alcohol, avoid paracetamol overuse and bring a list of medicines and supplements to the appointment. Keep a note of urine and stool colour and any itching.

The NHS route is a GP with urgent liver blood tests and ultrasound, then hepatology or surgery. Private hepatology and imaging provide rapid access to blood tests and MRCP.