Here is a new research article about treating PLE in Yorkies by diet only (no immunosuppressive drugs). The preliminary results are promising. The article is probably behind a paywall, but I'll copy the abstract below:
Dietary management of presumptive protein-losing enteropathy in Yorkshire terriers - Rudinsky - 2017 - Journal of Small Animal Practice - Wiley Online Library Abstract Objectives
To describe the clinical outcome of dietary management of Yorkshire terriers with protein-losing enteropathy without immunosuppressive/anti-inflammatory medications.
Methods
Records were searched for Yorkshire terriers with hypoalbuminaemia and a clinical diagnosis of protein-losing enteropathy that were managed with diet and without immunosuppressive/anti-inflammatory medications. Serum albumin changes were compared using a one-way repeated measures ANOVA. Canine chronic enteropathy clinical activity index scores were compared using a Wilcoxon signed-rank test.
Results
Eleven cases were identified. Clinical signs were variable including: diarrhoea, respiratory signs, vomiting, lethargy and weight loss. Diets fed included home cooked (n=5); Royal Canin Gastrointestinal Low Fat (n=4); Hill's Prescription Diet i/d Low Fat (n=1); or Purina HA Hypoallergenic (n=1). Clinical signs resolved completely in eight dogs, partially resolved in two dogs and failed to respond in one dog. In dogs that responded, albumin significantly improved from baseline (mean 14·9 g/L, sd ±3·7), at 2 to 4 weeks (mean 24·2 g/L, sd ±5·5, P=0·01), and at 3 to 4 months (mean 27·0 g/dL, sd ±5·9, P=0·01).
Clinical Significance
These results indicate that dietary management of protein-losing enteropathy is a potential management strategy in Yorkshire terriers. Randomised clinical trials in Yorkshire terriers with protein-losing enteropathy are necessary to compare success rate, survival and quality of life with dietary management
versus combined dietary and immunosuppressive/anti-inflammatory therapy.