Autoimmune Pancreatitis

The exact cause is not known. It is an immune-mediated condition: immune cells infiltrate the pancreas and cause swelling and fibrosis (scar tissue). It is not caused by alcohol or gallstones, and it is not infectious. Genetic and environmental factors may play a part, but nothing you did caused it.

It is a rare condition. Type 1 is seen more often in middle-aged and older men, and type 2 tends to affect younger people of both sexes. Because it is uncommon and can mimic pancreatic cancer, it is often found only after a specialist assessment.

Diagnosis needs a team approach because AIP can resemble pancreatic cancer. Doctors combine several clues: imaging (CT, MRI or endoscopic ultrasound) showing a swollen, sausage-like pancreas or a narrowed duct; blood tests including IgG4 levels (not always raised); evidence of other organ involvement; and, often, a tissue sample taken with a fine needle during endoscopic ultrasound to exclude cancer. Sometimes a short trial of steroids under specialist supervision is used when the picture is clear. Cancer must always be properly excluded first.

Daily habits cannot treat the disease but help you stay well on treatment.

• Take steroids exactly as prescribed and never stop them suddenly, since the body needs time to adjust.

• Do not drink alcohol and do not smoke, which can harm the pancreas.

• Keep all follow-up visits and scans, even when you feel well.

• Check your blood sugar if your doctor advises, particularly while on steroids.

• Tell your doctor about any signs of infection, and discuss vaccinations before starting immune-suppressing treatment.

There is no special diet for the disease itself, but diet helps manage the side effects of treatment and any pancreatic weakness.

• Eat a balanced diet with enough protein and calories; small frequent meals can help if appetite is poor.

• On steroids, limit sugary foods and drinks and reduce salt to help control blood sugar and fluid.

• Ask about calcium and vitamin D for bone protection during steroid treatment.

• If stools are greasy, tell your doctor; you may need enzyme replacement rather than a low-fat diet.

Treatment is decided and monitored by a specialist. Doses and length of treatment are individual and are never to be changed without advice.

• Corticosteroids (such as prednisolone) are the usual first treatment and are reduced slowly over weeks to months.

• Immune-modifying medicines (such as azathioprine) or rituximab may be used to prevent relapses.

• Your team may prescribe bone protection, stomach protection or diabetes medicine alongside steroids.

• Pancreatic enzyme capsules are given if digestion is affected.

• Report any side effects, including mood changes, poor sleep, high blood sugar, swelling or infection.

Procedures are used to confirm the diagnosis and to relieve blocked bile ducts.

• Endoscopic ultrasound with a needle sample helps to confirm the diagnosis and exclude cancer.

• A temporary stent (small plastic tube) placed through ERCP can open a blocked bile duct if jaundice is severe or there is infection.

• Surgery is avoided when the diagnosis is certain, but may be needed if cancer cannot be excluded.

International consensus criteria help doctors to diagnose AIP and tell the two types apart. Steroids remain first-line treatment, and for people whose disease returns, other immune-modifying medicines, including rituximab, are used in specialist centres. Ongoing research is looking at the best way to prevent relapses and the long-term risks of the disease.

Most people respond quickly to treatment, with jaundice and swelling improving over weeks. Type 1 disease can relapse, so follow-up is needed, sometimes with longer-term treatment. Type 2 relapses less often. Some people are left with reduced pancreatic function (needing enzymes) or diabetes. Regular follow-up helps to catch these early.

• Which type do I have, and could other organs be involved?

• Has cancer been properly excluded?

• How long will I take steroids and what side effects should I watch for?

• What is the chance of relapse, and what would we do?

• Do I need enzymes, or diabetes and bone checks?

This guide comes from the Saudi Gastroenterology Association (SGA) patient library, prepared by the Approved for publication by SGA; individual clinician review is ongoing. Last reviewed: 2026-04-24. It is for education and does not replace your doctor's advice.