Hi Juan,

Thanks for your question.

Cellulitis is inflammation of the tissues of the skin. There are a few different causes of cellulitis in dogs but the most common is a bacterial infection. It often occurs because of a traumatic penetration of the skin by a foreign body, such as a stick that inoculates the tissue underneath the skin with an infectious agent but there are many other causes as well.

I recommend you confirm the diagnosis with appropriate testing. Most veterinarians would agree that an X-ray is warranted to inspect the tissue for foreign material or any other type of lesions that could be causing the swelling (such as a broken bone, a mass pressing on surrounding vessels, or other defects). A sample of fluid could be collected and tested for different types of infectious agents that could be present.

You are currently administering an antibiotic for a suspected bacterial infection. Keep in mind that there are other infectious agents that could cause a lesion like this that are not a bacteria, such as a fungal infection. It is much more uncommon but since you mention that it is not improving, you may want to consider testing for this as a possibility. Keep in mind that certain bacteria can be resistant to specific antibiotics so performing a culture and sensitivity test would help identify this.

Hopefully this helps. Best of luck.

Dr. Clayton Greenway