What's this yellow fluid-filled bump under my puppy's armpit?

Thanks for using Petco Pet Education Center, formerly Petcoach! This could be a benign or malignant growth. Given his young age, this could just be a small abscess or site of infection. 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 him evaluated by your veterinarian for further assessment and treatment. I am really hoping for something benign. Good luck and have a good day!

Hello. This could just be a cyst or small tumor such as a histiocytoma. At this point, it does not look worrisome, so just monitor for any changes in size &/or shape. It is very unlikely to be dangerous, especially if it remains like this. Any changes though, please let your veterinarian take a look. 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!

Hi there and thank you for using Petco Pet Education Center, formerly Petcoach to address your concern. From the pictures, I suspect that what you are seeing is a insect bite or pustule. I would recommend monitoring it for now and if it worsens, becomes much larger or does not go away, I would recommend having the veterinarian recheck Maisy so that the most appropriate diagnostic and treatment recommendations can be made. You can apply a spray such as Malacetic conditioning spray to the area, which can be found online and do this twice daily until it resolves. I hope this helps! Please let me know if you have any other questions or concerns and I would be more than happy to help you further.

Thanks for using Petco Pet Education Center, formerly Petcoach! This looks like a focal infection. You can try to use a medicated shampoo containing chlorhexidine twice weekly for 2 weeks. If there is no improvement or in the meantime this appears to be getting worse, have her evaluated by a veterinarian for further assessment and treatment. Good luck and have a good day!

Hi and thanks for using Petco Pet Education Center, formerly Petcoach! The area in the picture looks like an area of what I would call excoriation or skin irritation usually seen when a dog scratches an area extensively due to itching. The yellowish area can be a pimple or what we call a pustule (a pimple containing pus). Pimples and pustules are usually raised lesions, extending up from the skin. It's a little difficult making out much detail in the picture. Sometimes damaged areas of skin turn yellowish like that and are usually flat in appearance, not raised up like a pimple/pustule. I hope this helps.

Hello. This looks like a possible infected hair follicle of sebaceous gland infection. It is probably not dangerous, especially since your dog is still quite young. I would gently clean the area with something like Hibiclens ( available at all pharmacies ) & if it seems to be getting worse, bothering your dog, or begins to ooze, please see your vet as soon as possible. Thanks for using Petco Pet Education Center, formerly Petcoach.