Modesto, Calif. — Lacey is a 6-year-old Pomeranian who runs the household. I bet there are a lot of us who might say the same thing about our dogs. Lacey spends her time indoors but is allowed to frolic in the back yard and goes on regular leash walks with Karen. Over the past few months, Karen has been dealing with a swelling on Lacey’s face just below her right eye. She has taken Lacey to her veterinarian and twice treated her with antibiotics; the last time, the treatment included prednisone. Each time, the swelling would disappear only to return a few days later. Karen is becoming discouraged, and in reading her letter, it is obvious she is worried about Lacey. Without question, Lacey’s facial swelling needs further investigation. Anytime a lesion is treated with antibiotics and there is resolution — whether permanent or temporary — there is likely to be bacterial infection involved. This does not mean that bacteria are the primary problem. there may be an underlying issue that allows a bacterial infection to secondarily occur. in Lacey’s case, there may be a tumor in the area of the swelling or perhaps a mass inside the nasal passage on the right side of Lacey’s face. I would think this less likely because antibiotics alone should not be able to reduce that type of swelling, as it is being caused by the growth of a mass. there is a possibility of a foreign body within the right nasal passage that has caused a secondary infection, which then causes swelling within the nasal passage that might then distort the right side of the face. I am not convinced this is the case. I am betting Lacey has an abscess in one or more of the roots of a tooth called the carnassial tooth. Technically, this tooth is a premolar, but typically it is the largest tooth in a dog’s mouth and has three roots. These roots are quite long and are anchored in the maxillary bone of the upper jaw. If there is an abscess in one or more of these roots, it can cause erosion of the thin layer of bone separating the tip of the root(s) from the nasal passage. This then can cause swelling of the face precisely in the described location of Lacey’s lesion. to diagnose a carnassial abscess, we simply need to take some dental radiographs and look for a tooth root abscess. The molar behind the carnassial tooth could also be a culprit. Armed with the information provided by the radiographs, we can then go about fixing the problem. Depending on the individual case and preference of the caretaker, we can do a root canal of the offending root(s) or elect to simply extract the tooth. once either procedure is done and yet another course of antibiotics is finished, Lacey will be cured. JEFF KAHLER is a veterinarian in Modesto, Calif. Questions can be submitted to your Pet in care of LifeStyles, The Modesto Bee, P.O. Box 5256, Modesto CA 95352.