The most common causes of pancreatitis are:drinking excessive amounts of alcohol; having gallstones in the bile duct; taking certain medicines, eg azathioprine and corticosteroids; abdominal injuries; a tumour in the pancreas; having undergone an endoscopic ultrasound; an infection with a virus such as mumps or the Epstein-Barr virus; increased calcium or lipid (fat) levels in your blood; pancreas divisum-being born with ducts in the pancreas which don't function properly; genetics-you may inherit a faulty gene from your parents(hereditary pancreatitis); cystic fibrosis, or inflammation of the blood vessels in your pancreas or reduced blood flow to your pancreas.
Attribution: BUPA