Here is a technical article on PLE in dogs that should be accessible to everyone:
http://www.wvc.org/images/session_no.../2013_S17A.pdf
It describes the diagnosis, causes, and treatment of PLE in dogs. Apparently, there are three major types of PLE:
(1) Intestinal Lymphangiectasia, which is a common form of PLE found in Yorkies.
(2) Inflammatory Bowel Disease, which is the most common form found in Wheaten Terriers.
(3) Crypt disease.
Other causes of PLE are alimentary lymphoma and fungal infections (histoplasmosis).
Treatment of PLE includes modifying the diet and using medicines to control the underlying inflammation. Here is an excerpt from the article about dietary changes:
"Diet: Dogs with PLE are in a catabolic state, and adequate nutrition is essential. There are currently no published studies critically evaluating nutritional aspects of canine PLE. However, a large body of clinical experience is available. In dogs with primary idiopathic IL, dietary modification centers on feeding a highly digestible diet with low to very low fat content (10-15% on a dry matter basis) to prevent further dilation and rupture of lacteals. Additionally, the diet should contain highly bioavailable dietary proteins and be low in crude fiber. While drug therapy may be administered for a few months (see below) and then discontinued in some cases, dietary therapy should probably be maintained for the length of the dog’s life. In dogs with PLE associated to underlying IBD, many veterinary gastroenterologists report good success with exclusive feeding of a diet consisting of hydrolyzed proteins. Novel protein diets are an alternative approach.
Acceptance of the diet is a critical issue in PLE dogs, particularly in the most severely affected animals, which may be anorexic. For each patient, the veterinary care team needs to identify the most palatable diet. Initially, it might be more important to feed a less optimal diet that the dog will be interested in eating, and progressively transition to a more desirable diet."