25-year-old woman, smoker of about 10 cigarettes/day, with no other history of interest. She was admitted for symptoms of > 5 diarrhoeal stools, sometimes accompanied by blood and weight loss. Colonoscopy was performed and normal colonic mucosa was observed. In the terminal ileum, three irregularly shaped ulcerations with a fibrinous background were seen. Biopsies were taken, confirming the diagnosis of Crohn's disease. Laboratory tests showed an albumin level of 2,890 mg/dl with no other findings. She was referred to the Nutrition Department, where no protein catabolism, reduced intake or other causes of malnutrition were observed. A1AT in blood: 159 mg/dl; A1AT in stool: 1.28 mg/g; stool weight in 24h: 182.84 g. A1AT clearance was 147.19 ml/day (> 56 ml/day), confirming the diagnosis of PLE. After treatment with azathioprine and hyperprotein nutritional supplements, the patient improved clinically, with serum albumin rising to 3,270 mg/dl.