Or it could just be teeth coming in. Both my girls teethed early and fast. My 17 month old has 6 teeth coming in right now and boy does the saliva flow. Best of luck!
I have three boys and one girl...your talking about a boy...? i thought it was funny that all my boys had siliva problems but my daughter didnt...i think thats normal..but always confirm with your doctor i would lime to know if that was normal too...