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Autoimmune pancreatitis
Covenant Metabolic Specialists Health Library
Covenant Metabolic Specialists
Physician Reviewed
Dec 3, 2025
Autoimmune pancreatitis (AIP) is a rare form of chronic pancreatitis caused by the body’s immune system attacking the pancreas. Often mistaken for pancreatic cancer due to similar symptoms, AIP typically responds well to steroid therapy and is part of a broader group of IgG4-related diseases. Accurate diagnosis is critical to avoid unnecessary surgery and long-term complications.
What is Autoimmune Pancreatitis?
Autoimmune pancreatitis is a type of chronic inflammation in the pancreas triggered by immune dysregulation. It causes swelling and narrowing of the pancreatic ducts, leading to obstructive symptoms like jaundice or abdominal discomfort. There are two distinct subtypes:
Type 1 AIP (IgG4-related): A systemic condition that can also affect the bile ducts, kidneys, and salivary glands.
Type 2 AIP: Limited to the pancreas and more often linked to inflammatory bowel disease (IBD).
Both types are treatable, but require different monitoring strategies.
Symptoms
Symptoms of AIP may resemble those of other pancreatic or biliary diseases:
Painless jaundice (yellowing of the skin and eyes)
Abdominal discomfort or fullness
Weight loss
Dark urine, pale stools
New-onset diabetes or worsening glucose control
Fatigue
Mild pancreatitis symptoms (e.g. nausea, indigestion)
Enlarged, firm pancreas on imaging
In Type 1 AIP, symptoms outside the pancreas may include:
Dry mouth
Enlarged lymph nodes
Renal dysfunction
Salivary gland swelling
Causes
Autoimmune pancreatitis is caused by abnormal immune activity targeting the pancreas and, in Type 1, other organs.
Type 1 AIP (IgG4-related disease): Overproduction of IgG4 antibodies, causing inflammation and fibrosis
Type 2 AIP: Thought to be immune-mediated, but not linked to IgG4; often coexists with ulcerative colitis or Crohn’s disease
The exact triggers remain unknown but may involve genetics, environmental factors, or chronic inflammation.
Risk Factors
Age:
Type 1 usually affects men > 60
Type 2 more common in younger adults
Sex: Type 1 is more common in males; Type 2 affects men and women equally
Family history of autoimmune disease
Presence of IBD (for Type 2 AIP)
Asian descent (higher prevalence in Japan, Korea)
Diagnosis
Diagnosis can be challenging due to similarity with pancreatic cancer.
Common diagnostic tools include:
Blood tests: Elevated IgG4 levels (Type 1 only), liver enzymes, pancreatic enzymes
Imaging:
CT or MRI showing a diffusely enlarged “sausage-shaped” pancreas
Narrowed pancreatic or bile ducts
Endoscopic Ultrasound (EUS): May reveal hypoechoic mass or allow for fine-needle biopsy
Histology: Confirms lymphoplasmacytic infiltrate and fibrosis
Steroid trial: A rapid response to prednisone may help confirm AIP and rule out malignancy
Biopsy may be essential to exclude pancreatic cancer.
Treatments
Autoimmune pancreatitis typically responds well to steroids, with most patients improving within weeks.
First-line treatment:
Prednisone 30–40 mg daily × 4 weeks, followed by tapering over 2–3 months
Monitor blood glucose closely (especially in older adults)
Biliary stenting may be needed temporarily if bile ducts are obstructed
Relapse prevention or maintenance (in recurrent cases):
Azathioprine, mycophenolate, or rituximab (especially for IgG4-related Type 1)
Ongoing monitoring for relapse with labs and imaging every 3–6 months
Prevention
There is no proven way to prevent autoimmune pancreatitis, but proactive monitoring is key for those at risk:
Manage coexisting autoimmune diseases (e.g., IBD, lupus)
Regular imaging and labs if you’ve had AIP in the past
Avoid unnecessary pancreatic surgery by getting an accurate diagnosis
Work with a specialty team that understands IgG4-related conditions
Our Take
Autoimmune pancreatitis is often mistaken for cancer—and we’ve seen patients scheduled for major surgery when a steroid trial was all they needed.
At Covenant, we take time to look deeper, test thoroughly, and treat early. If you’ve got pancreatic inflammation and jaundice without pain, we’re checking for AIP—because the right call changes everything.
Schedule an evaluation with our team today.
