Expert: Dr. Louis N. Gotthelf - 7/20/2007

Question
We have an 11 year old beagle/dachsund mix that is being treated for pyoderma(sp).  She looks very moth eaten and has several large sores still on her body.  She's been on Cephalexin for approx. 6 weeks.  She has had a good appetite until the past few days and now she won't eat and she has two oval shaped knots near her private area.  She seems to be losing weight quickly.   Thank you.

Answer
If she has been on Cephalexin with no help for 6 weeks, it is most likely not a skin infection with bacteria.  There are so many things that can look like that including mange, fungal disease, sebaceous adenitis, cutaneous lymphoma and pemphigus. It is worrisome when lymph nodes get big (the oval shaped knots).  My suggestion would be either to get a second opinion, or ask your vet to do skin biopsies of the active lesions to see what the disease might be.