Q. My 8 year old chihuahua was neutered before he was 2 years old. I just noticed some swelling in the perianal area that is new.
DR. MASSIMO ORIOLES, DVM, MRCVS
A. It is unlikely that the swelling is related to the previous castration surgery.
The swelling is possibly arising from the anal glands (inflammation, infection or even possibly a tumoral growth) or the perianal/anal tissues ( muscles or skin for example). It is very difficult to be more specific at this stage and I would need more informations to be able ( eventually a picture) to be able to tell you exactly what it is. I would recommend to have him checked by your veterinarian or request a consultation to discuss the problem further.