For the past 4 days, we have been greeted in the morning by some very foul smelling and messy diarrhea from our 2 year old son. The diarrhea has varied in consistency (from very watery at first to thicker and more lumpy most recently) and color (started out green and is now more brown). He hasn't eaten anything new or unusual recently that would be causing this (that we know of). We also noticed today that his belly and belly button are protruding more than normal. He also has what appears to be diaper rash around his anus, but it was almost purple at first, then became lighter after using Desitin consistently with each new diaper change.

My 3 year old daughter had awful diarrhea , sounds the same . She had just a normal virus . And the coloring around the bumhole is probably because of the diarrha . When you have it , your bum burns and will eventually turn red or so after a few times in your case , days of having it . But to b safe you should bring him to the doctors ! Goodluck ! :)

Go to the doctor. This is your kid, don't play games. 4 days is a little extreme to still be just guessing at what may be wrong.

Dehydration in children this young can be very dangerous to the point of being life threatening. Get that baby to a doctor A.S.A.P.