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DrLucy, Dog Veterinarian
Category: Dog Veterinary
Satisfied Customers: 618
Experience:  Almost 30 yr as a practicing small animal vet.; experience in gen.medicine, surgery, emerg/
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Hello, My dog began growing what looked like an extra nail

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My dog began growing what looked like an extra nail out of one of her paw pads. The first two times we brought her into the vet, they claimed it was just an extra toe nail. When the nail grew almost three times the size of a normal nail, we brought her in for a third time. They now say it's viral, and that the test of the nail sample was inconclusive. What could this be and how can I help her? It had begun to be painful to her. She constantly licks at it (which we always try to stop) and it bleeds if she licks/gnaws at it when we are not around.

Thank you for your help!
Hello, I'm Dr. Bob.
I would suggest asking your veterinarian to remove the "extra nail". This can be done quite simply, but will require anesthesia.
If the nail were not bothering Sienna, I'd recommend leaving well enough alone, but as it is, it needs to come off to give her relief from the pain and irritation.
If you should have further questions, please let me know.
Customer: replied 7 years ago.
Thanks for trying, but I am really looking for someone who may know the cause of this more than anything. I've been told the nail can grow back after being removed, so while I am willing to have this removed once to try, putting her under anesthia every 6 months is just not an option. I am trying to see what this is and if there are any other preventative methods I can use to keep this from happening.
It sounds like it could be a Cutaneous Horn, which is often caused by a papillomavirus. The best plan is to have it removed (with aggressive depth of sampling), with a biopsy that is sent to a dermatopathologist (not just a standard pathology lab). On the biopsy, they can distinguish between another toenail, a true cutaneous horn, or some other lesion, such as simple footpad hyperkeratosis, a corn, or a tumor.

Although there is a chance of it recurring (if it is caused by a papillomavirus), there has been some success with interferon treatment. In addition, the antibiotic azithromycin has shown some success with treatment of papilloma on the skin or mucous membranes, but has not been studied in cutaneous horns. My suggestion is that, if the biopsy does come back as a virally induced lesion, you consult a dermatology specialist, who will know the latest in treatment approaches.

If you would like to post a close-up photo, I would be happy to see if there is anything else that comes to mind. I might also be able to show that photo to a dermatologist to get another opinion.

I hope that this is what you had in mind by your question. I would be happy to provide you with more information, including pictures of the possibilities that I mentioned. Please let me know if you need any clarification.
DrLucy, Dog Veterinarian
Category: Dog Veterinary
Satisfied Customers: 618
Experience: Almost 30 yr as a practicing small animal vet.; experience in gen.medicine, surgery, emerg/
DrLucy and other Dog Veterinary Specialists are ready to help you
Customer: replied 7 years ago.
Thank you so much! This is very helpful. My vet was very uneducated on this and I want to be able to ensure I know as much as possible to ensure Sienna receives the proper treatment for this. I googled images of cutaneous horns and it looks very similar. It looks similar to a nail, but very feathery in texture and has grown to be larger. She is such a sweet dog and I hate to see her uncomfortable like this and want to do my best to prevent this from re-occurring. Thanks again!
If it is just feathery looking, it might be just hyperkeratosis. Although hyperkeratosis lesions can be caused by the papillomavirus, they can also be caused by uneven wear on the foot pad. Normal foot pads are always growing keratin on them. During the course of normal wear, the keratin is rubbed off and the pads stay relatively smooth. If the pad does not rest evenly on the ground, the part with less pressure tends to overgrow keratin projections. If this is the case, applying a keratin-softening product like Kerasolve (which contains salicylic acid). Kerasolve is a veterinary product, but Dr. Scholl's footcare products may have something similar, if you check the pharmacy.

Here are two pictures. The first is a true Cutaneous Horn. The second (on the right) is Footpad hyperkeratosis. Either one could be caused by a papillomavirus. However, uneven wear can cause hyperkeratosis that is NOT viral in origin.