Head to toe look. Caress your pet make it comfortable. While petting him you can run your hand easily over the animals body. Caress the head, shoulders, underside and backside. Basically you are looking for any bumps,lumps,tumors,warts,and cyst.
Weight loss is a common sign of disease.
Stand back and view the entire hair coat. If so this can be a surface signal of a disorder inside. This can be signs of allergy. And Gums- Begin with the mouth. Move inside the mouth check the teeth see if any are broken or coated with excess tartar.