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Why does my dog keep getting itchy red spots with hair loss?

Updated On September 23rd, 2025

Pet's info: Dog | Goldendoodle | Female | spayed | 2 years and 9 months old | 15 lbs

Sammie has had 3 of these type of spots in the past 3 months. She experiences hair loss, and then develops redness with a circle. We’ve taken her to the vet numerous times and they keep thinking it’s an allergy. We did an allergy test and are awaiting results, but want a second opinion.

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1 Answer

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Answered By Catherine Stecyk

Veterinarian

Published on April 22nd, 2019

Hello and thank you for reaching out to Petco Pet Education Center, formerly Petcoach. This spot looks like a "hot spot", or moist dermatitis. These occur from a dog licking repeatedly at a particular area, causing hair loss and severe irritation of the skin. This causes trauma to the skin, resulting in superficial bacterial infections that are very itchy and can create a constant cycle of itching and licking. Sammie should wear an Elizabethan collar at all times that she has any of these hot spots to prevent her from licking and causing further trauma. Hot spots occur because of any underlying problem, most often allergies. The top skin allergies in dogs include flea allergies, food allergies, and atopic dermatitis (or environmental allergies). I would ensure that Sammie is on a veterinarian-approved flea and tick preventative consistently. The next most common allergy is a food allergy, and the only way to diagnose this is with a diet trial, or an elimination trial. This requires feeding either a 'novel protein diet' (meaning it has a protein that Sammie has never eaten before, i.e. such as venison, or salmon) or feeding a 'hydrolyzed protein diet', which has protein molecules too small for the immune system to have a reaction to. In order for this diet trial to be effective, whatever food you choose must be the ONLY thing that Sammie eats for 8 weeks! That means no treats, no human foods, etc. If her clinical signs of itching resolve with the exclusive diet, then Sammie is likely allergic to whatever protein was in her previous diet. I hope this is helpful! Allergies can be frustrating in dogs... and most veterinary dermatologists do not actually believe that "allergy tests" are helpful. All they show are what antigens dogs have been exposed to previously, but they do not specifically say what dogs are allergic to.

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