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Why does my dog have a red, pus-filled rash on her belly/thighs?

Updated On September 23rd, 2025

Pet's info: Dog | Mixed Breed | Female | unspayed | 60 lbs

My dog seems to have a rash or something on her under belly, inner thighs and down toward her lady part. It’s very red and a big section has pus .. I don’t know what it is or what to do ..

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2 Answers

Most Helpful Answer

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Answered By Ricardo Fernandez, DVM

Veterinarian, Veterinary Oncology Resident

Published on November 27th, 2017

Thanks for using Petco Pet Education Center, formerly Petcoach! This could be due to allergies for example. It really comes down to figuring out what is causing her allergies so that they can be treated or the specific allergen avoided. There are many things that can cause allergies though in most cases they can be broken down into 3 big categories: flea, food and environmental allergies. Allergies are usually worked up in a stepwise fashion starting with flea allergies as this is the easiest and cheapest to take care of. If not on a flea preventative, then it would be a good idea to get started on one. If already on one then it would be a good idea to change to something else (there are many new products out in the market). If not improved in 1-3 months then it is time to move on and check for food allergies by switching to a novel diet (new protein and new carbohydrate). If that does not seem to be the issue then you are left out having to check for environmental allergies which require blood and/or skin tests. Allergies can be very frustrating to deal with at first but so rewarding at the end when we are able to treat them effectively!

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Other Answers

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    Answered By Dr. Leigh, DVM

    Veterinarian

    Published on February 15th, 2019

    It is difficult to diagnose without seeing the lesion but it could be a bacterial skin infection, fungal infection, or allergic dermatitis. She should be examined by a vet to determine the cause and treat. You could also try Vetricyn Spray and see if that helps, too.

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