Cullen’s sign occurs due to tracking of haemorrhagic fluid from the retro-peritoneum along the gastrohepatic and falciform ligament to the umbilicus.

Why does pancreatitis cause Cullen's sign?

Cullen’s signSpecialtyVarious

Why does pancreatitis cause retroperitoneal bleeding?

In severe acute pancreatitis, the injured pancreas releases pancreatic enzymes that cause fat necrosis and inflammation, occasionally resulting in peri-pancreatic bleeding.