5 yo Ds has lost about two pounds since late last fall. He was always skinny (10th percentile or so) and now is down around third. Would you worry? What could it be? Anyone experience this or hear of it? TIA.

Spoke to him on the phone. At first said call me back if he loses two more pounds in the next few months. Then he changed his mind, put him on a pediasure drink, and said if he doesn't gain it back in a month come in...