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What's causing my puppy's painful armpit rash and what should I do?

Updated On September 23rd, 2025

Pet's info: Dog | Mixed Breed Small (up to 22lb) | Female | unspayed | 5 months and 28 days old | 21 lbs

My beagle/ jack russel six month puppy has a rash under her armpit that is really bugging her and looks very painful. She is also not acting like herself (very tired, clingy). I just want to know what it is and what I should do.

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4 Answers

Most Helpful Answer

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Answered By Dr. Elizabeth

Veterinarian

Published on July 21st, 2019

Those spots on Bella could be several things including allergies, skin mites, flea bites, ringworm (which humans can get) or a bacterial infection. You can try adding in an omega 3 fatty acid supplement for dogs, this can help improve the skin health. You may also try changing her diet to something like Royal Canin or Nutro as they are aimed at skin health. The best option is to have Bella examined since the rash is bothering her. This will figure out the cause the fastest and bring her relief sooner. If you cannot get to the veterinarian's office, you can wash the lesions with soap once a day and rinse well (don't wash her whole body, just those spots). Protect the areas from licking or scratching with an elizabethan collar. If they don't start looking better within about a week or if they get worse, have her examined by his veterinarian who may prescribe medications. Best of luck and please feel free to post any additional questions.

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    Answered By Megan, DVM, CVA

    Veterinarian

    Published on February 8th, 2018

    Poor Bella! This could be due to fleas or some type of allergy. I would make sure she is on a high quality flea preventative like advantage, cheristan, or comfortis. You can also try to give her Benadryl twice a day to see if This helps. You can also try a calming shampoo like duoxo calming. Unfortunately if she not improving or if she has a lot of scabs, she may need something stronger. I would have your vet take a look at her to see if she needs some antibiotics and even stronger allergy meds like steroids. I hope this helps. https://www.petcoach.co/canigive/cat/benadryl/

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    Answered By C. Rathjens, DVM

    Veterinarian

    Published on April 3rd, 2019

    Poor girl, that looks very uncomfortable. I would be very suspicious that Bella has allergies to something that she's still being exposed to. The most common causes of allergies are food, fleas, and the environment (like human hay fever). I would recommend going back to the vet to confirm there isn't something more acute going on (like a new superficial infection) and then discuss possibility of allergies. She may need a longer course of antibiotics and/or oral steroids to calm her immune system down as well.

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    Answered By Dr. Elizabeth

    Veterinarian

    Published on July 6th, 2017

    I would wonder is Bella has allergies. The photos didn't come out well on my side but it looks like scabs maybe? I think you should look for an antibacterial shampoo for dogs and wash her in it twice a week. You could also give her an over the counter antihistamine which may help with the itching. If these don't work, I think you should take her into the vet for a stronger medication. In general, the more Bella itches at those areas, the worse she will make them.

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