There are several reasons for a sudden suborbital (below the eye) swelling in dogs – insect bites are indeed possible, but more commonly we should think of trauma, foreign body, tumor and definitely dental disease.
In dogs, discoloured teeth with intact crowns are non-vital in majority (92.2%) of the cases. These teeth can be infected and painful. Therefore, they should be carefully examined and radiographed. It is recommended to treat discoloured teeth.
When the tooth is affected with endodontic disease, either due to fracture or periodontal trauma, treatment is required.