dogs belly

Question
My little mix breed (terrier/poodle) has constant tears in his eyes.
His belly is also turning a darker color. Is this allergy related? Normal? A
problem?

Answer
The eye tearing could be conjunctivitis, blocked tear ducts, allergies, or abnormalities of the eyelashes and eyelids.

The belly color may be perfectly normal, particularly if he gets in the sun, but there are also a couple other conditions that can cause skin darkening, one of which is called acanthosis nigricans. http://www.peteducation.com/article.cfm?cls=2&cat=1592&articleid=518  

Your dog needs to be seen by a veterinarian for a diagnosis.