Q: My 7-month-old cat has a swollen bottom lip. He is drooling a little bit. I was wondering if it could be a symptom of calicivirus.
A: I doubt that this is calicivirus. Your cat’s “fat lip” is probably a manifestation of a condition (with a crazy long name) called the feline eosinophilic granuloma complex. This is an inflammatory skin condition in which the immune system sends inflammatory cells called eosinophils into various regions of the body.
Sometimes these inflammatory cells affect the skin on the back of the thigh. Other times, it appears as raised red lesions on the abdomen. My own cat, Crispy, suffers from this. The mouth is another common place for this to occur. Often, an erosion will appear on the upper lip. This usually is referred to as a rodent ulcer. Sometimes, the bottom lip is affected, causing the swollen “fat” lip. Treatment consists of giving corticosteroids, either by mouth or via injection. In most cases, the condition resolves readily with treatment, although recurrence is possible.
Please see your veterinarian as soon as possible to ensure your cat gets adequate treatment.