A mother brings a boy, 1 year old, to the Emergency Department with a 5 month history of diarrhea which is described as frequent soft stools. There is no blood in the stool. The child has not been vomiting and has abdominal pain. The child is in daycare. The child is fully immunized and is formula fed plus a variety of solids. Family history reveals that the child's father has hypothyroidism. On examination the child looks well. The vital signs are as follows, bp: normal, hr: normal and temp: 37.3°C. Abdominal examination is normal. Perianal examination is normal. Skin examination is normal.