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My 1-year-old dog has a growing pimple in her armpit. What is it?

Updated on September 23rd, 2025

Pet's info: Dog | Mixed Breed Medium (23 - 60lb) | Female | spayed | 1 year old

My 1 year old healer has a pimple/blister in her armpit. It started out small but has doubled in size in the last week. She has had it for about a month.

2 Answers

Most Helpful Answer

Ricardo Fernandez, DVM

Answered By Ricardo Fernandez, DVM

Veterinarian, Veterinary Oncology Resident

Published on November 25th, 2017

Thanks for using Petco Pet Education Center, formerly Petcoach! This could be a benign or malignant growth. This is often differentiated by a test called a fine needle aspirate (FNA) which is a pain free, inexpensive and easy procedure which in most cases will help reach a diagnosis. Sometimes a biopsy is needed for a definitive diagnosis. I recommend that you have her evaluated by your veterinarian for further assessment and treatment. I am really hoping for something benign. Good luck and have a good night!
Vote Icon2Pet Parents found this answer helpful

Related Answers from Veterinarians

  • Answered By Ricardo Fernandez, DVM

    Veterinarian, Veterinary Oncology Resident

    Published on January 4th, 2018

    Thanks for using Petco Pet Education Center, formerly Petcoach! This could be a benign or malignant growth. This is often differentiated by a test called a fine needle aspirate (FNA) which is a pain free, inexpensive and easy procedure which in most cases will help reach a diagnosis. Sometimes a biopsy is needed for a definitive diagnosis. I recommend that you have her evaluated by your veterinarian for further assessment and treatment. I am really hoping for something benign. Good luck and have a good day!

    Vote Icon

    1Pet Parents found this answer helpful

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