Inflammed vulva

Question
Our 6-year old female beagle began having an inflammed vulva area about 6 months ago.  The vulva becomes red and has small blisters.  The irritation, if left unchecked, becomes knotty under the skin near her mammaries.  These knots have been removed and analyzed with no clear disease--definitely not cancer.  We have treated her with doxicycxline and prednisone.  We have been unable to discontinue the pred without the inflammation returning.  Her fur is now thin, which may be a result of the pred or perhaps it's another symptom of the underlying disease which our vets have not been able to diagnose. Her thyroid has been checked and it's normal.  Do you have any ideas of what could be wrong?  We're concerned about the long term use of pred even though it's a low dose.

Answer
Low dose pred has very few long term side effects.  There is a steroid spray that you can try called Genesis or you can try a steroid powder, which may keep the vulvar fold from getting too moist. I would not use Doxycycline for any type of skin problem because it does not kill skin organisms very well.  If there is no bacterial infection, then antibiotics may not be needed.