My female dog has swelling on one side. What could be the problem?

Thanks for using Petco Pet Education Center, formerly Petcoach! This is likely unrelated to her hypothyroidism. It may be the site of an infection or inflammation. They may be able to confirm this tomorrow and start antibiotics as needed to make her feel better. Good luck!

Thanks for using Petco Pet Education Center, formerly Petcoach! Based on the swelling's location, this is possibly due to a tooth root abscess. This is something your veterinarian could check for on an examination and treat if confirmed. This is something that is treated with local therapy including drainage, debridement and antibiotics. Good luck and have a great day!

Thanks for using Petco Pet Education Center, formerly Petcoach! You may be describing inflammation, an infection, hematomas or even growths. To know how to better manage this, it would be needed to reach a diagnosis. For that reason, I recommend that you have him evaluated by a veterinarian for further assessment and treatment. They would be able to check for these possibilities and treat him accordingly. Best of luck!

Thanks for using Petco Pet Education Center, formerly Petcoach! It is not possible to know what is exactly going on just based on a picture. This could be due to an infection or an allergic reaction for example. I would highly recommend that you have her evaluated by a veterinarian for further assessment and treatment. They would be able to check for these possibilities and treat accordingly. Good luck!

Hello. This is probably benign mammary hyperplasia, but you do want to have this looked at, especially if she has been spayed. If she has not been spayed & has never been with a male dog, then this could be related to a false pregnancy. Also, has she been in contact with anyone who is on hormone replacement therapy? Sometimes, this can rub off on a pet & cause mammary enlargement. If no outside cause can be found, then have her spayed if that has not already been done, & submit a biopsy to see exactly what is going on with the tissue. Thanks for using Petco Pet Education Center, formerly Petcoach.

Thanks for using Petco Pet Education Center, formerly Petcoach! This could be a benign or malignant growth. This is often differentiated by a test called a fine needle aspirate (FNA) which is a pain free, inexpensive and easy procedure which in most cases will help reach a diagnosis. Sometimes a biopsy is needed for a definitive diagnosis. I recommend that you have her evaluated by your veterinarian for further assessment and treatment. I am really hoping for something benign. Good luck and have a good night!

I am sorry to hear about Chocolat. There are numerous possible causes for this swelling. These could include a pseudopregnancy (where the body for some reason thinks it is pregnant and starts producing milk), mastitis (an infection of a mammary gland), mammary gland hyperplasia (a noncancerous swelling of the mammary tissue), tumors of the mammary gland (not common in dogs this young but not impossible), or a benign tumor such as a fatty tumor such as a lipoma that just happens to be over the area of the mammary chain. I would recommend an exam at your vet to help determine the cause and appropriate treatment. They may recommend an aspirate of the area with a needle to help identify what the cause of the swelling is and how best to treat it.