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Why does my puppy have a red, spreading rash under his back legs?

Updated On September 23rd, 2025

Pet's info: Dog | Mixed Breed Medium (23 - 60lb) | Male | 1 year and 2 months old

Hi my name is Shannon. My 1 year old puppy suddenly got a red patch of skin under his back leg (Armpit). I noticed it seemed irritated so I chalked it off as him scratching himself on something... however it appears to have gotten worse and even moved under his other hind leg. I was wondering if it’s a serious problem or will heal itself?

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1 Answer

Most Helpful Answer

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Answered By Dr. Leigh, DVM

Veterinarian

Published on April 16th, 2019

It looks like he has a skin infection so he should be examined by a vet to determine the cause and treat. He may need an antibiotic and anti-inflammatory and your vet can prescribe. You could bathe him with a medicated shampoo, like Douxo Chlorhexidine shampoo and see if that helps, too.

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