Foot Problems in Cats
Cutaneous horn formation on cat's foot
Question: Dear Dr. Richards, About 15 mos. ago, we noticed our 5 yr. old cat, Annie, making a "clicking" noise when she walked and assumed she needed her nails clipped, which we did, but it continued. We discovered a rough crusty patch on the order of a wart or callus on the big pads of both front paws. We took her to the vet, which she had only seen this once before and proceeded to explain the possibility of an auto-immune disease. It was removed on the left paw and sent to be analyzed. There was no bacteria, fungi or parasites observed, but in a study done, cats with cutaneous horns also tested positive for the luekemia virus, however no inflammation or viral infection was see, but recommended the FELV and FIV test be done, which was already done before we let her in our house. We had an IFA test done along with FIV which was negative. We have since decided to remove the other "horn" as it seems to bother her. The top layer hardens and falls off only to grow back again. The other "horn" never returned after surgery, though there seems lately to be a little rough spot where it was taken off. Since the pathologist was unable to identify this we are wondering if you have ever heard of this rare disorder or what it could be. Annie is a very healthy cat with no other symptoms, which you would think something would have occurred by now. Our vet says it could be a lazy virus. Please give us some insight into this problem. We would appreciate it very much. Thank you, Cherie
There are a number of suspected underlying causes for cutaneous horn formation on cat footpads or other areas (sometimes these occur on the face or other areas). In our practice, though, we see a lot of these that we can't find any underlying cause for. Among the known underlying causes are squamous cell carcinoma, a form of cancer, and the reason that a biopsy was probably done. Fortunately, that doesn't appear to have been the cause. More commonly, these are linked to feline leukemia virus or feline immunodeficiency virus infection, although lots of cats are negative for both of these viruses when the cutaneous horns are found, as well, just like yours.
When no underlying cause can be found it is OK just to trim these down to the level of the footpad when they start to bother the cat. These usually don't have a blood supply and it is possible to trim them using a nail trimmer without causing pain (or at least not apparent pain). Some people use keratolytic solutions, such as Kerasolve (tm) to dissolve these but we haven't tried this since we have good luck just trimming the horns and since cats tend to lick ointments or solutions off their feet.
I do think it would be a good idea to watch carefully for signs of a more severe problem, such as a tumor, developing at or near the site of the cutaneous horns but the odds of this happening are pretty low.
It is entirely possible that some day a viral underlying cause will be identified since a lot of vets seem to think that a virus is the most likely culprit as a cause of this problem.
Mike Richards, DVMLast edited 02/01/05