Overview

Autoimmune pancreatitis (AIP) is a chronic inflammation that is thought to be caused by the body's immune system attacking the pancreas and that responds to steroid therapy. Two subtypes of AIP are now recognized, type 1 and type 2.

Type 1 AIP is the pancreatic manifestation of a disease called IgG4-related disease (IgG4-RD). This disease often affects multiple organs including the pancreas, bile ducts in the liver, salivary glands, kidneys and lymph nodes.

Type 2 AIP seems to affect only the pancreas, although about one-third of people with type 2 AIP have associated inflammatory bowel disease.

Type 1 AIP can be mistakenly diagnosed as pancreatic cancer. The two conditions have overlapping signs and symptoms, but very different treatments, so it is very important to distinguish one from the other.