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My dog is biting a red, thinning patch on his back. What could it be?

Updated On September 23rd, 2025

Pet's info: Dog | Mixed Breed Small (up to 22lb) | Male | unneutered | 8 years and 10 months old | 14 lbs

Hello, I have a Bichon Frise poodle, 8 years of age. He is a very happy and playful, energetic boy. As of last week, I noticed a small patch on his back. The patch is slightly redish-brown and the hair there looks a bit less dense than the rest of his coat. Today i saw him biting on it, however it doesnt seem to bother him too much or when i touch it. He is eating well, also going to the washroom well. He runs around and looks like nothing is bothering him. What can this be? Thank you, Tomek

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2 Answers

Most Helpful Answer

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Answered By Ana M, DVM

Veterinarian

Published on May 10th, 2018

Thank you for submitting your question regarding Bingo. It sounds like he is itching if he is biting his side. He could be experiencing seasonal allergies as those are a big source of itching in a dog this time of year. Be sure to check him over for fleas as well. Other causes of itching are a mild skin infection, an insect bite or sting or a small skin mass. I would start by bathing him with a moisturizing shampoo and conditioner such as an oatmeal or fatty acid based formula. If this does not relieve his symptoms, then he will need to see his veterinarian. I hope this information helps!

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    Answered By Jennifer Summerfield, DVM CPDT-KA

    Veterinarian, Certified Dog Trainer

    Published on May 30th, 2017

    Poor Jack! This area of skin does look very red and sore. The red marks you are seeing are likely due to him chewing and biting at this area - this is very common in dogs who have skin problems that cause excessive itching, such as allergies or skin mites (mange). He may also have a bacterial or fungal skin infection contributing to the itching and redness. Treatment will depend on what the underlying problem is, so I would recommend taking Jack to the vet for an exam as soon as you are able to. He/she can do some simple skin tests to help determine what is causing the itching, and get him started on appropriate medication to treat it depending on what is found. In the meantime, you may need to put an e-collar (plastic cone) on Jack to prevent him from continuing to chew at this area and make things worse.

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