zoey

Question
My dog recently developed a rash on her left armpit which is spreading.  It looks like little red bumps but the bumps seem to be swelling. I was able to pop one of the bumps and a fluid came out.  She doesn't seem to be itching them although I don't know if she could even reach.  She is a miniature dachshund and is 10 months old.

Answer
The bumps you described are termed vesicles and are primarily caused by virus, contact allergy (such as poison ivy or oak) or immune mediated disease.  If they have resolved on their own and not recurred I would expect virus or contact allergy and no treatment should be needed.  If however they have continued I would recommend having her seen by your veterinarian to evaluate her.

My humble apologies for the delayed response.  A family illness detained me.