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What causes a swollen nipple on an unspayed dog that's getting worse?

Updated On September 23rd, 2025

Pet's info: Dog | Mixed Breed Small (up to 22lb) | Female | unspayed | 10 years and 4 months old

My dog has a swollen nipple and its gotten progressively worse what could it be?

1 Answer

Most Helpful Answer

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Answered By Dr. Melanie, BVSc MS

Veterinarian

Published on January 27th, 2018

I see that Brandy isn't spayed. When dogs aren't spayed, they are prone to developing mammary tumors. There is a 50% that a mammary tumor can be malignant, and it's concerning that her swollen nipple is getting larger. I would take her into a vet as soon as possible. The vet can diagnose if she does have a mammary tumor, and if she does have one, if it's malignant or not. Malignant tumors will have to be removed surgically. Please take her into a vet this weekend or first thing Monday. Good luck, I hope this helps!

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