<<He sweats excessively and I have read an article which states that allergic
children can sweat a lot.>>
Just a thought:
When mom kisses him does he taste salty?  I worry about sweating babies with
skin rashes and the possibility of cystic fibrosis.
<<The child is offered all kinds of finger foods and sometimes takes them and
eats a small amount.>>
I remember Kittie Frantz reminding parents that a child will eat about the
same amount that will fit into his hand.  Not much given that visual picture.
My advice is to find what he will eat and leave it in reach, so he can feed
himself.
In questioning mothers with the problem of baby doesn't seem to be taking
solids, I often find that mom responds to the baby's feeding cues by nursing
and not offering solids.  (I was guilty of this with my son and breakfast.
Who wants to get out of bed to get the food when it is right there?) A simple
inventory of mom's actions should be all that is needed.
My only concern would be iron and related HGB, & HCT levels.  If they are OK
why worry?
Marie Davis