Dear Christopher Cat
My cat Kibbles’ upper lip is very swollen. My vet diagnosed rodent ulcer and gave her a shot. What exactly is rodent ulcer? Kibbles lives indoors, and I can’t imagine how she could have eaten a mouse.
Rodent ulcer, or eosinophilic ulcer, is one of several manifestations of feline eosinophilic inflammatory disease.
The term rodent ulcer only reflects the characteristic appearance of the upper lip. The disease isn’t caused by eating mice!
Eosinophils, or “eos,” are white blood cells associated with allergy. They are thought to invade certain areas of skin if the cat is allergic to flea saliva, inhalants such as pollens, or even some food ingredients.
Eosinophilic ulcers may affect one or both upper lips. When eos invade other skin areas (especially the chin, the backs of the thighs, belly, or ears), the diseases are termed eosinophilic plaque and eosinophilic granuloma complex.
Eosinophilic lesions respond to steroid tablets or injection, but they may recur if the allergic trigger remains in the cat’s environment.