Tak:
Yup. Look at his Vitamin A or carotene intake. Does he eat a lot of carrots, drink a lot of vegetable juice? A serum (blood) test for carotene may help clarify things.
Carotenemia is harmless; most kids aroind a year old look a little yellowish, because they eat yellow vegtables and don't metabolize carotene as well. Adults only get yellow palms if they eat a real lot of the stuff.
Another possibility: the palms and soles may have gotten thicker, giving them a yellowish cast.
Maybe a dermatologist should check it out.
Best.
Dr. Rockoff