Canker Sore Overview. Canker sores, also known as aphthous ulcers, are among the most common causes of painful sores in the mouth. 1  The classic lesion is a small (less than 1 centimeter) oval to round ulcer with a erythematous (red) border.2  They occur on the mucous membranes inside the mouth.anker Sore Overview. Canker sores, also known as aphthous ulcers, are among the most common causes of painful sores in the mouth. 1  The classic lesion is a small (less than 1 centimeter) oval to round ulcer with a erythematous (red) border.
Other Causes of Heavy Panting in Dogs. Heavy breathing or deep, intense panting can also be a symptom of eclampsia, also called milk fever. Eclampsia is a dangerous condition that affects nursing mothers; low blood calcium levels lead to an inability to stand or walk and tremors.
Jaundice is not always contagious to other dogs. This will be determined by the cause of the condition. Jaundice in dogs can be caused by various factors such as: 1  Drug administration (i.e., corticosteroids, Phenobarbital or chemotherapy).2  Liver damage. 3  Toxicity (due to ingestion of poisonous materials).side from the heartworms, the other conditions that cause jaundice are not contagious. The heartworm may be transmitted to other canines, but only through mosquito bites. A mosquito can transmit heartworms from one canine to another if it bites an infested dog.