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What causes red spots and a nickel-sized bump on my dog's arm?

Updated on September 23rd, 2025

Pet's info: Dog | Dachshund | Female | spayed | 4 years and 11 months old

I noticed these red spots on/under my dogs arm with a little bit of redness on her skin to the right of the pictures. There is also a nickel sized bump under her skin. Any idea on what this could be? I'm going to vet school and have looked through books and can't figure it out. She has an appointment next week.

1 Answer

Most Helpful Answer

Stephanie Echols, DVM

Answered By Stephanie Echols, DVM

Veterinarian

Published on September 18th, 2017

Thanks for using Petco Pet Education Center, formerly Petcoach! The red bumps looks like a bacterial infection. I would try washing the area with mild soap and water. If they persis for 24 hours I would see a vet for antibiotics. The bump under the skin is very difficult to diagnose. I would recommend having a vet stick a needle in the lump and look at the cells under the microscope. It could just be fat cells (lipoma) but there is no way to know without diagnostics. Good luck and kisses to Dalylah!
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