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Why is my puppy's side lump getting worse and losing fur?

Updated On September 23rd, 2025

Pet's info: Dog | Belgian Malinois | Female | spayed | 7 months and 16 days old | 30 lbs

My dog has had a lump on her side for about a week now. It has not reduced in size. She is 6 months old. The lump under the skin is about the size of a peanut. It was smooth at first. Then a few days into it, it was an open sore. Then it scabbed over. It doesn't bother her, she doesn't scratch it. But she doesn't like me touching it. We live in Southern Maine. She is also now losing fur where the bump is located.

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1 Answer

Most Helpful Answer

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Answered By Daniel Fonza, DVM

Veterinarian

Published on May 16th, 2018

Hi there and thank you for using Petco Pet Education Center, formerly Petcoach to address your concern. Based on the picture and your description, I suspect this is benign and likely to be an insect bite or cyst. If it does not resolve completely within the next week or the hair loss worsens, I would get him seen sooner rather than later. I hope this helps guide you in the right direction. Please let me know if you have any other questions or concerns and I would be more than happy to help you further. Please take the time to mark this question as helpful or not as it helps us to improve on the quality of our answers to other pet owners. Thank you kindly!

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