Q: I adopted a female cat who looks like a flame-point Himalayan a year ago who has now developed a sore underneath her chin. I’m familiar with “stud-chin” in cats, so I know to feed her from a stainless steel bowl, and I’m pretty sure that’s not the problem.
I went to my cat’s vet last week and my cat got a shot of Convenia and was put on an ointment of Mupirocin. Still, the sore is there. Could it possibly be a food allergy? My cat continues to eat well, plays well and doesn’t seem to be bothered by the sore on her chin.
A: I’ve heard of “stud-tail” but never “stud-chin.” I suspect you mean “chin acne.” Chin acne is a bacterial infection of the hair follicles on the chin resulting in cat acne. In the past it has been suggested that a contact allergy to plastic could be a cause of chin acne, with a recommendation that cats be fed from a glass, stainless steel or porcelain food bowl rather than a plastic one. In reality, plastic food bowls are rarely, if ever, the cause of chin acne. The fact the sore on the chin developed despite feeding your cat from a stainless steel bowl is no reason to rule out chin acne as the cause of the sore.
Antibiotics, however, are usually effective at resolving chin acne. The antibiotic your vet chose, Convenia, is an excellent choice for chin acne. The topical antibiotic Mupirocin is also an excellent antibiotic for chin acne. In my experience, the vast majority of cat chin acne cases resolve when this combination of systemic and topical antibiotics is used. I suspected your cat did indeed have chin acne, but the lack of response to this combination makes me question this diagnosis. Food allergy is a possibility, but a single sore on the chin would be a very unusual presentation in a cat with food allergy.
I’m glad your cat is not bothered by the sore. Whether or not the sore should just be monitored by you at home is something that your cat’s veterinarian needs to decide. If this sore is actually some type of ulcerated skin mass, it may be prudent to consider performing a biopsy or removing it altogether. You should discuss this with your veterinarian.