Collagenous enterocolitis manifesting as watery diarrhoea and iron-deficiency anaemia

A 56-year-old Caucasian woman presented with epigastric pain, watery diarrhoea, bloating and flatulence following treatment with duloxetine and venlafaxine for anxiety and depression. Abdominal examination was benign. Blood work revealed haemoglobin of 96 g/L (115–160 g/L), iron 6 μmol/L (10–33 μmol/L), transferrin saturation 0.08 (0.20–0.55), ferritin 26 μg/L (15–180 μg/L), albumin 46 g/L (35–50 g/L), pre-albumin 293 mg/L (170–370 mg/L), total IgA 2.64 g/L (0.78–3.58 g/L) and anti-tTG IgA 5 units (