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Rodent Ulcers

Rodent ulcers are open sores found primarily on the inside of the cat's upper lip, adjacent to the canine tooth. They sometimes develop in other sites, on the tongue, lips roof of the mouth or on the skin of the abdomen or inner thigh.

The term "Rodent" ulcer is misleading. It originated because it was thought these sores were due or infections contracted from mice or tats. Their real cause is still uncertain, but is is generally believed they are the result of constant irritation from the cat's rough tongue. The reason why only some cats develop them in not understood.

The sore are usually oval in shape, with a raised edge or border. The affected area is gradually eroded. It becomes red and inflamed and may bleed intermittently especially if knocked.

Early in its course, the ulcer is small and caused little concern to the cat. As it progresses, eating can become uncomfortable, and the cat may lose its appetite salivate and paw at the mouth.


Some cases respond to treatment with drugs such as cortisone, or hormones. In advanced cases, surgical removal may be contemplated although this can be deforming. X-ray treatment, cryosurgery and injections into and around the sore have been successful in some selected cased. Treatment is not always successful and recurrence is common.