Immune disorders - Several possibilities have been suggested. The low concentrations of IgA reported in the intestine of German Shepherd Dogs may be a factor leading to reduced local immunity allowing antigens to cross the mucosal barrier of the intestine , and there setting up an inflammatory response in the lamina priopria.
Drugs - prostaglandin synthetase inhibitors (cincophen and indomethacin) , non-steroidal antiinflammatory drugs (NSAIDs) and cholinergic agents have all be implicated as possibly causing inflammatory bowel disease.
Diet - some of the suggested possibilities for dietary influence are:
- food additives e.g. carrageenan, sulfated amylopectins and lignosulfonates can cause colitis in studies.
- dietary antigens - based on response to changes in diet. Likely but not proven.
- dietary deficiencies - vitamin A, folic acid, pantothenic acid - cause colitis in studies.
Infectious agents - infectious agents have been found in affected animals, but no direct link has yet been proven.
Other suggested causes: parasites, increased bowel permeability, ischaemia, biochemical and psychological causes.